bluuebunny/crossref_metadata_2025_split huggingface dataset:
DP-TABU: an algorithm to solve single-depot multi-line vehicle scheduling problem
Authors: Xinchao Zhao , Hao Sun , Juan Lu , Zhiyu Li 
Published: June 2021

AbstractA DP-TABU algorithm is proposed which can effectively solve the multi-line scheduling problem of single Deport (SD-ML-VSP). The multi-line regional coordinated dispatch of the single-line deport of the bus is to solve the problems of idle low-peak vehicles and insufficient peak capacity in single-line scheduling. The capacity of multiple lines at the same station is adjusted to realize resource sharing such as timetables, vehicles, and drivers. Shared capacity such as bus departure intervals and bus schedules. Taking the regional scheduling of multiple lines at the same station as the service object, a vehicle operation planning model based on the objective of optimal public transportation resources (minimum bus and driver costs) is established to optimize the vehicle dispatching mode of multiple lines. We applied this algorithm to the three lines S105, S107, and S159 of Zhengzhou Public Transport Corporation, and the results proved that the algorithm is effective. Through comparison with manual scheduling and simulated annealing algorithm, the advantages of DP-TABU algorithm in performance optimization and robustness are further verified.
Aggregation-Induced Emission in Electrochemiluminescence: Advances and Perspectives
Authors: Moreno-Alcántar Guillermo , Aliprandi Alessandro , De Cola Luisa 
Published: June 2021

Abstract
The discovery of aggregation-induced electrochemiluminescence (AIECL) in 2017 opened new research paths in the quest for novel, more efficient emitters and platforms for biological and environmental sensing applications. The great abundance of fluorophores presenting aggregation-induced emission in aqueous media renders AIECL a potentially powerful tool for future diagnostics. In the short time following this discovery, many scientists have found the phenomenon interesting, with research findings contributing to advances in the comprehension of the processes involved and in attempts to design new sensing platforms. Herein, we explore these advances and reflect on the future directions to take for the development of sensing devices based on AIECL.

Graphic abstract
Nonlinear emergent macroscale PDEs, with error bound, for nonlinear microscale systems
Authors: Bunder J. E. , Roberts A. J. 
Published: June 2021

AbstractMany multiscale physical scenarios have a spatial domain which is large in some dimensions but relatively thin in other dimensions. These scenarios includes homogenization problems where microscale heterogeneity is effectively a ‘thin dimension’. In such scenarios, slowly varying, pattern forming, emergent structures typically dominate the large dimensions. Common modelling approximations of the emergent dynamics usually rely on self-consistency arguments or on a nonphysical mathematical limit of an infinite aspect ratio of the large and thin dimensions. Instead, here we extend to nonlinear dynamics a new modelling approach which analyses the dynamics at each cross-section of the domain via a multivariate Taylor series (Roberts and Bunder in IMA J Appl Math 82(5):971–1012, 2017. 10.1093/imamat/hxx021). Centre manifold theory extends the analysis at individual cross-sections to a rigorous global model of the system’s emergent dynamics in the large but finite domain. A new remainder term quantifies the error of the nonlinear modelling and is expressed in terms of the interaction between cross-sections and the fast and slow dynamics. We illustrate the rigorous approach by deriving the large-scale nonlinear dynamics of a thin liquid film on a rotating substrate. The approach developed here empowers new mathematical and physical insight and new computational simulations of previously intractable nonlinear multiscale problems.
Effects of contamination with gasoline on engineering properties of fine-grained silty soils with an emphasis on the duration of exposure
Authors: Yazdi Abdollah , Sharifi Teshnizi Ebrahim 
Published: June 2021

AbstractLeaking tanks may lead to severe contamination of their surrounding soil. The geotechnical behavior of the soil varies with the physicochemical processes that occur between the contaminant and the soil. In this respect, studying the geochemical properties of gasoline-contaminated soils and sediments seems to be important for engineering and especially environmental purposes. In this paper, laboratory tests were carried out to examine the effects of crude gasoline contamination on some of the geotechnical properties of a silty soil sampled from the Mashhad plain, located in the northeast of Iran. Tests consisted of basic properties, Atterberg limits, compaction, direct shear, and uniaxial compression tests, which were carried out on clean and contaminated soil samples at the same densities. The contaminated samples were prepared by mixing the soils with crude gasoline in the amounts of 3%, 6%, 9%, and 12% of dry weight and curing periods of 0, 7, 15, and 30 days. Results indicated a decrease in the friction angle and an increase in the cohesion of the soil by increasing gasoline content. Besides, a reduction in the maximum dry density and optimum moisture content was observed in the compaction test. The increase in gasoline percentage up to 6% also showed a direct effect on increasing the liquid limit and plastic limit of silty soil, which decreased thereafter. Moreover, any increase in gasoline percentage had a reverse effect on the modulus of elasticity of the soil. The increase in gasoline percentage up to 3% also had a direct impact on the uniaxial compressive strength of the soil, exceeding which it started to decline. Finally, the effects of contamination duration were examined by testing contaminated samples in periods of 7, 15, and 30 days under natural conditions. The results showed a reverse relationship with all geotechnical properties due to aging and a reduction in the gasoline content due to the evaporation of volatile compounds. Also, the numerical analysis of the laboratory results indicated an increase in settling and the percentage of shear strain beneath the foundation with increasing the contamination level, confirming the laboratory results.
Investigating forest fragmentation through earth observation datasets and metric analysis in the tropical rainforest area
Authors: Pyngrope Osaka Ruandache , Kumar Mukesh , Pebam Rocky , Singh Sudhir Kumar , Kundu Arnab , Lal Deepak 
Published: June 2021

AbstractExtensive mining operations, deforestation, jhumming, and soil erosion coupled with population stress in the study area have put an adverse effect on its forest resources. This study investigates the transition in forest cover classes and its fragmentation in the Jaiñtia Hills District of Meghalaya (India). Satellite data (multispectral images from Landsat 5 and 8) for 1995, 2001, 2007, and 2015 were classified using the supervised classification method. Landscape metrics from the classified images were calculated using FRAGSTATS. The overall accuracy of classification was found to be 87.50% (1995), 87.50% (2001), 85.00% (2007) and 91.67% (2015), respectively. The results revealed an increase in dense forest with an increase in the patch number from 1995 to 2007. Additionally, a decrease in non-forest cover with an increase in the number of patches from 2001 to 2015 was observed which further suggests fragmentation. It has been reported that 8.13% of the dense forest increased and 19.47% of non-forested areas decreased during the study period. Overall, this study highlights the changes in the distribution of forest area which could aid policy makers to adopt appropriate forest conservation strategies.
Modeling and optimization of cutting forces and effect of turning parameters on SiCp/Al 45% vs SiCp/Al 50% metal matrix composites: a comparative study
Authors: Laghari Rashid Ali , Li Jianguang 
Published: June 2021

Abstract
In this study, the proposed experimental and second-order model for the cutting forces were developed through several parameters, including cutting speed, feed rate, depth of cut, and two varying content of SiCp. Cutting force model was developed and optimized through RSM and compared for two different percentages of components SiCp/Al 45% and SiCp/Al 50%. ANOVA is used for Quantitative evaluation, the main effects plot along with the evaluation using different graphs and plots including residual analysis, contour plots, and desirability functions for cutting forces optimization. It provides the finding for choosing proper parameters for the machining process. The plots show that during increment with depth of cut in proportion with feed rate are able to cause increments in cutting forces. Higher cutting speed shows a positive response in both the weight percentage of SiCp by reducing the cutting force because of higher cutting speed increases. A very fractional increasing trend of cutting force was observed with increasing SiCp weight percentages. Both of the methods such as experiment and model-predicted results of SiCp/Al MMC materials were thoroughly evaluated for analyzing cutting forces of SiCp/Al 45%, and SiCp/Al 50%, as well as calculated the error percentages also found in an acceptable range with minimal error percentages.

Article Highlights

This study focuses on the effect of cutting parameters as well as different percentage of SiC particles on the cutting forces, while comparing the results of both SiC particles such as SiCp/Al 45%, and SiCp/Al 50% the result shows that there isn’t fractional amount of impact on the cutting force with nominal increasing percentages of SiC particles.

Cutting speed in machining process of SiCp/Al shows positive response in reducing the cutting forces, however, increasing amount of depth of cut followed by increasing feed rate creates fluctuations in cutting force and thus increases the cutting force in the cutting process.

The developed RSM mathematical model which is based on the box Behnken design show excellent competence for predicting and suggesting the machining parameters for both SiCp/Al 45%, and SiCp/Al 50% and the RSM mathematical model is feasible for optimization of the machining process with good agreement to experimental values.
Comparing Tropopause‐Penetrating Convection Identifications Derived From NEXRAD and GOES Over the Contiguous United States
Authors: Cooney John W. , Bedka Kristopher M. , Bowman Kenneth P. , Khlopenkov Konstantin V. , Itterly Kyle 
Published: June 2021

AbstractOvershooting tops (OTs) are a well‐known indicator of updrafts capable of transporting air from the troposphere to the stratosphere and generating hazardous weather conditions. Satellites and radars have long been used to identify OTs, but the results have not been entirely consistent due to differences in sensor and measurement characteristics. OT detection approaches based on satellite infrared (IR) imagery have often been validated using human‐expert OT identifications, but such datasets are time‐consuming to compile over broad geographic regions. Despite radar limitations to detect the true physical cloud top, OTs identified within multi‐radar composites can serve as a stable reference for comprehensive satellite OT analysis and detection validation. This study analyzes a large OT data set compiled from Geostationary Operational Environmental Satellites (GOES)‐13/16 geostationary IR data and gridded volumetric Next‐Generation Radar (NEXRAD) reflectivity to better understand radar and IR observations of OTs, quantify agreement between satellite and radar OT detections, and demonstrate how an increased spatial sampling from GOES‐13 to GOES‐16 impacts OT appearance and detection performance. For nearly time‐matched scenes and moderate OT probability, the GOES‐13 detection rate (∼60%) is ∼15% lower than GOES‐16 (∼75%), which is mostly attributed to coarser spatial resolution. NEXRAD column‐maximum reflectivity and tropopause‐relative echo‐top height as a function of GOES OT probability were quite consistent between the two satellites however, indicating that efforts to account for differing resolution were largely successful. GOES false detections are unavoidable because outflow from nearby or recently decayed OTs can be substantially colder than the tropopause and look like an OT to an automated algorithm.
Recent Advances in Detection of Overshooting Cloud Tops From Longwave Infrared Satellite Imagery
Authors: Khlopenkov Konstantin V. , Bedka Kristopher M. , Cooney John W. , Itterly Kyle 
Published: June 2021

AbstractThis paper describes an updated method for automated detection of overshooting cloud tops (OT) using a combination of spatial infrared (IR) brightness temperature patterns and modeled tropopause temperature. IR temperatures are normalized to the tropopause, which serves as a stable reference that modulates how cold a convective cloud should become within a given region. Anvil clouds are identified using histogram analysis and cold spots embedded within anvils serve as OT candidate regions. OT candidates are then assigned an OT probability, which can be interpreted as a metric of storm intensity and an estimate of confidence in a detection for a particular pixel. It is produced using an original mathematical composition of four factors: Tropopause‐normalized temperature, prominence relative to the surrounding anvil, surrounding anvil area, and spatial uniformity of anvil temperature, which are calculated from empirically derived sensitivity curves. The shape of the curves is supported by independent analysis of a large sample of matched IR and radar‐derived OT regions. An optimal sensitivity for each factor was determined by maximizing correlation between the OT probability and a set of human‐identified OT regions. Coarser spatial resolution of GOES‐13 data cause OTs to be less prominent compared to GOES‐16, necessitating different sensitivities for each satellite. Detection performance is quantified for each satellite based on human OT identifications and as a function of how prominent the OT appeared in visible and IR imagery. Based on analyses of human‐identified OTs, OT detection accuracy, defined by the area under a receiver operating characteristic curve, is determined to be 0.94 for GOES‐16 and 0.78 for GOES‐13.
Implementation and Impacts of Surface and Blowing Snow Sources of Arctic Bromine Activation Within WRF‐Chem 4.1.1
Authors: Marelle Louis , Thomas Jennie L. , Ahmed Shaddy , Tuite Katie , Stutz Jochen , Dommergue Aurélien , Simpson William R. , Frey Markus M. , Baladima Foteini 
Published: June 2021

AbstractElevated concentrations of atmospheric bromine are known to cause ozone depletion in the Arctic, which is most frequently observed during springtime. We implement a detailed description of bromine and chlorine chemistry within the WRF‐Chem 4.1.1 model, and two different descriptions of Arctic bromine activation: (1) heterogeneous chemistry on surface snow on sea ice, triggered by ozone deposition to snow (Toyota et al., 2011 https://doi.org/10.5194/acp-11-3949-2011), and (2) heterogeneous reactions on sea salt aerosols emitted through the sublimation of lofted blowing snow (Yang et al., 2008, https://doi.org/10.1029/2008gl034536). In both mechanisms, bromine activation is sustained by heterogeneous reactions on aerosols and surface snow. Simulations for spring 2012 covering the entire Arctic reproduce frequent and widespread ozone depletion events, and comparisons with observations of ozone show that these developments significantly improve model predictions during the Arctic spring. Simulations show that ozone depletion events can be initiated by both surface snow on sea ice, or by aerosols that originate from blowing snow. On a regional scale, in spring 2012, snow on sea ice dominates halogen activation and ozone depletion at the surface. During this period, blowing snow is a major source of Arctic sea salt aerosols but only triggers a few depletion events.
Volatile Element Evidence of Local MORB Mantle Heterogeneity Beneath the Southwest Indian Ridge, 48°–51°E
Authors: Wang Wei , Kelley Katherine A. , Li Zhenggang , Chu Fengyou , Dong Yunpeng , Chen Ling , Dong Yanhui , Li Jie 
Published: June 2021

AbstractThe mantle source beneath the Southwest Indian Ridge (SWIR) reflects a complex history of contamination. Magmatic volatile contents are vital tracers of these kinds of heterogeneities, which may fractionate otherwise constant volatile/non‐volatile elemental ratios, such as the H2O/Ce ratio. Although several studies have recently used trace element and isotopic data to address mantle source heterogeneity and magmatic processes at SWIR 48°–51°E region, volatile element constraints provide a valuable test of models for the origins of mantle heterogeneities in this region. Here, we present new data for nine rare basaltic glass samples from the 48°–51°E region, which enable careful assessment of the effects of primary versus secondary processes on the glass volatile contents. These samples are strongly affected by variable extents of carbon degassing, and shallow assimilation of Cl‐rich fluid, but also reveal consistently high H2O/Ce ratios (458.8 ± 14.9), among the highest in MORBs, that cannot be explained by late‐stage secondary processes, crustal assimilation, or simple melting of peridotite mantle at variable depths. Instead, the high H2O/Ce ratios are features of the mantle source composition. The 48°–51°E region is notably more depleted in highly incompatible trace elements relative to other regions of the SWIR, although this depletion is not apparent in H2O, which is similarly abundant throughout the SWIR. We link the high H2O/Ce ratios in these glasses with other trace element characteristics diagnostic of subduction and fluid addition, suggesting that the mantle source reflects signatures of a refractory mantle residue that previously melted within a subduction zone.
Observation of Unusual Chorus Elements by Van Allen Probes
Authors: Liu Si , Gao Zhonglei , Xiao Fuliang , He Qian , Li Tong , Shang Xiongjun , Zhou Qinghua , Yang Chang , Zhang Sai 
Published: June 2021

AbstractWhistler mode chorus waves play an important role in the radiation belt dynamics, which usually appear as discrete elements with frequency sweeping. Finer structure analysis shows that a chorus element is composed of several frequency‐sweeping subelements, and such two‐level structures can be successfully reproduced by modeling based on nonlinear theories. Previous observations and models suggest that an element and its subelements should have the same frequency‐sweep direction. However, we here present two unexpected chorus rising tone events within which the subelements exhibit clearly reversed, falling frequency‐sweep. Moreover, the subelements consist of several wave packets that also show falling frequency‐sweep features. The three‐level structured chorus elements are distinctly different from all the reported observations and seem to bring challenges to the existing theories. We propose a possible scenario that the falling tone subelements are formed by nonlinear process with much shorter timescale and the starting frequency of each subelement is controlled by fast varying electron distribution. This study may inspire more studies toward a thorough understanding of the chorus generation process.
Submarine Meltwater From Nioghalvfjerdsbræ (79 North Glacier), Northeast Greenland
Authors: Huhn Oliver , Rhein Monika , Kanzow Torsten , Schaffer Janin , Sültenfuß Jürgen 
Published: June 2021

AbstractThe Greenland Ice Sheet (GrIS) faces accelerated melting under a warming climate. This also affects the largest marine‐terminating outlet glacier of the Northeast Greenland Ice Stream (NEGIS), the Nioghalvfjerdsbræ (79 North Glacier, 79NG). In the cavity below its floating ice tongue, the heat of inflowing warm and saline Atlantic Water melts the ice at the base, and colder and fresher outflow is exported toward the shelf break and presumably south with the East Greenland Current (EGC). However, freshwater from submarine melting is hardly distinguishable from other freshwater sources by salinity alone. To identify and to quantify the distribution of submarine meltwater on the Northeast Greenland Shelf, we use helium (He) and neon (Ne) observations obtained directly at the calving front of the 79NG, on the Northeast Greenland Shelf, and in Fram Strait during an expedition aboard R/V POLARSTERN in summer 2016. These tracers uniquely identify submarine meltwater (SMW) and allow quantifying its fraction. SMW is present on the shelf but dilutes from 1.8% at the 79NG calving front to nonsignificant in Fram Strait. The SMW formation rate of the 79NG was estimated to be 14.5 ± 2.3 Gt per year. A surplus of Ne compared to He in the upper 100 dbar observed on most of the shelf region is attributed to noble gas fractionation during sea ice formation. Combining the Ne excess with the ventilation time on the shelf of 1.5 years yields a mean sea ice formation rate of 4 m per year.
First Documented Downward Positive Cloud‐to‐Ground Lightning Initiated by an Upward Negative Lightning
Authors: Jiang Ruijiao , Lyu Weitao , Wu Bin , Qi Qi , Chen Lyuwen , Ma Ying , Lyu Fanchao , Zhu Yanan , Rakov Vladimir A. 
Published: June 2021

AbstractAn interesting downward positive cloud‐to‐ground lightning (DPCG) initiated by an upward negative cloud‐to‐ground lightning (UNCG) was recorded by the instruments installed at the Tall‐Object Lightning Observatory in Guangzhou. The characteristics of the discharges before and after the DPCG return stroke were investigated in detail using both optical and electric field change data. The UNCG was triggered from the tip of the Canton Tower (600 m high) by a distant +CG lightning. A sequence of intracloud (IC) discharges developed toward and connected to several pre‐existing channels of the UNCG. As a result, some positive charge was pumped from remote thundercloud regions to the region around the intersection of the pre‐existing and new channels. A branch of one IC channel developed from the intersection point toward the ground, transformed into a downward positive leader, terminated on the ground, and resulted in a positive return stroke. After that, the discharge processes in the cloud continued to neutralize the remaining positive charge. The UNCG served to facilitate the IC discharges that supplied positive charges for the DPCG. Most of the charge involved in the UNCG‐initiated DPCG originated from remote positively charged regions in the cloud. These observations constitute evidence for a new scenario of the initiation of +CG lightning.
Blue Flashes as Counterparts to Narrow Bipolar Events: The Optical Signal of Shallow In‐Cloud Discharges
Authors: Li Dongshuai , Luque Alejandro , Gordillo‐Vázquez F. J. , Liu Feifan , Lu Gaopeng , Neubert Torsten , Chanrion Olivier , Zhu Baoyou , Østgaard Nikolai , Reglero Víctor 
Published: June 2021

AbstractNarrow Bipolar Events (NBEs) are powerful radio emissions from thunderstorms, which have been recently associated with blue optical flashes on cloud tops and attributed to extensive streamer electrical discharges named fast breakdown. Combining data obtained from a thunderstorm over South China by the space‐based Atmosphere Space Interactions Monitor, the Vaisala GLD360 global lightning network and very low frequency/low frequency radio detectors, here we report and analyze for the first time the optical emissions of blue luminous events associated with negative NBEs and located at the top edge of a thundercloud. These emissions are weakly affected by scattering from cloud droplets, allowing us to estimate the source extension and optical energy involved in the process. The optical energy in the 337‐nm band emitted by fast breakdown is about 104 J, which involves around 109 streamer initiation events.