Adjacent Sources Research Articles

The Application of Copula Continuous Extension Technique for Bivariate Discrete Data: A Case Study on Dependence Modeling of Seismicity Data

The Copula approach for continuous variables is highly developed, while discrete ones are underdeveloped due to computational difficulties and sometimes algorithm failure to convergent. Therefore, providing an alternative method for discrete variables becomes an essential issue. In this paper, a simple method is proposed to answer the problem by applying the Continuous Extension Technique (CET). This is carried out by adding random independent perturbations in the form of either Uniform distribution U(0,1) or (U(0,1)−1), and the discrete variables are treated as continuous. Subsequently, a Copula model for resulted variables is estimated based on the Copula theory for continuous variables. This method is called a Copula continuous extension technique. Our analytic and simulation approaches show that both random perturbation forms produce the same Kendall’s Tau measure and the selected Copula bivariate model. As illustrations, the proposed method is applied to the seismicity data obtained from the annual frequencies of earthquakes that occurred in the Sumatra megathrust of Indonesia, from January 1971 to December 2018, with magnitudes ( Mw ) of at least 4.6. Based on the selected Copula models, our simulations confirm the evidence of dependence seismic activity in each of the two adjacent large earthquake sources. These results provide new information regarding the seismicity behavior in the Sumatra megathrust.

Occurrence, spatial distribution, and fate of polycyclic musks in sediments from the catchment of Chaohu Lake, China.

Twenty-nine surface sediments from Chaohu Lake in China and from its six main tributaries were sampled to investigate the concentrations of two important polycyclic musks (PCMs), 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran (galaxolide, HHCB) and 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (tonalide, AHTN), as well as the concentration of 4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta(g)-2-benzopyran-1-one (galaxolidon, HHCB-lactone), which is the main degradation product of HHCB. Except for the high concentrations of AHTN and HHCB measured in the Nanfei River (879ng/g dw and 5,513ng/g dw, respectively), the levels of AHTN and HHCB in the river sediments were 7.08-44.9ng/g dw and 20.6-268ng/g dw, respectively, which are slightly lower than those documented in various areas worldwide. The concentrations of AHTN and HHCB in the sediments of Chaohu Lake were one or two orders of magnitude lower than those in the tributary rivers and showed a clear regional distribution. The concentrations of HHCB-lactone were comparable to those of HHCB and presented a significant positive correlation with the concentrations of HHCB, suggesting that the HHCB-lactone originated directly from the degradation of HHCB in wastewater treatment plants (WWTPs) or in the natural environment. The diagnostic ratios of HHCB/AHTN and HHCB-lactone/HHCB and the enantiomeric fractions (EFs) of these PCMs showed that the direct origins of the target PCMs in the study area were municipal and industrial wastewaters discharged from adjacent cities or point sources and that the HHCB-lactone in sediment originated from the natural degradation of HHCB in the rivers and the lake. The results of the risk assessment showed that the PCMs in the watershed sediments were unlikely to pose a threat to aquatic species. However, the effluents of industrial and municipal wastewaters that are discharged into the Nanfei River should be investigated in future research.

Trend analysis of anthropogenic activities affecting trace metals deposition in core sediments from the coastal and four rivers estuary of Sarawak, Malaysia.

This study reports the concentrations of trace metals in core sediments profile from the coastal and four rivers estuary in the Kuching Division of Sarawak, Malaysia, and the controlling mechanisms influencing their availability in sediments of the studied area. The bonding of trace metals with non-mobile fractions was confirmed with the sequential extraction. Inductively coupled plasma-optical emission spectroscopy (ICP-OES) was used to measure the concentrations of the trace metals. Granulometric analyses were performed using normalized sieve apertures to determine the textural characteristics of the sediments. Enrichment factor was used to evaluate the level of metal enrichment. Heavy metals concentrations in sediment samples varied in the range: Pb (8.9-188.9mg/kg d.w.), Zn (19.4-431.8mg/kg d.w.), Cd (0.014-0.061mg/kg d.w.), Ni (6.6-33.4mg/kg d.w.), Mn (2.4-16.8mg/kg d.w.), Cu (9.4-133.3mg/kg d.w.), Ba (1.3-9.9mg/kg d.w.), As (0.4-7.9mg/kg d.w.), Co (0.9-5.1mg/kg d.w.), Cr (1.4-7.8mg/kg d.w.), Mg (68.8-499.3mg/kg d.w.), Ca (11.3-64.9mg/kg d.w.), Al (24.7-141.7mg/kg d.w.), Na (8.8-29.4mg/kg d.w.), and Fe (12,011-35,124.6mg/kg d.w.). The estimated results of the enrichment factor suggested enrichments of Pb, Zn, and Cu in all the core sediment samples and depths at all sites. The other trace metals showed no enrichments in almost all the sampled stations. Continuous accumulation of Pb, Zn, and Cu metals over a period can be detrimental to living organisms and the ecology. The results obtained from the statistical analyses suggested that the deposition of trace metals in the studied sites is due to anthropogenic inputs from the adjacent land-based sources.

Use of multiple light sources to enhance the resolution of point light source displays.

The point light sources (PLSs) of integral imaging displays have a wide depth range; however, the resolution is very low. We developed resolution-enhanced PLS displays using multiple light sources that create extra PLSs in the PLS plane. Given aberrations in the lens arrays, the PLSs initially appeared on planes and at distances that differed from the theoretical values. We thus determined the distances between adjacent light sources that compensated for the aberrations. Experimentally, our method enhanced the resolution fourfold compared to that of a conventional PLS display in both vertical and horizontal directions. Our approach allows facile compensation of lens array aberrations and is applicable to 3D displays.

Indoor and Outdoor Nanoparticle Concentrations in an Urban Background Area in Northern Sweden: The NanoOffice Study

In recent years, nanoparticles (NPs) have received much attention due to their very small size, high penetration capacity, and high toxicity. In urban environments, combustion-formed nanoparticles (CFNPs) dominate in particle number concentrations (PNCs), and exposure to those particles constitutes a risk to human health. Even though fine particles (<2.5 µm) are regularly monitored, information on NP concentrations, both indoors and outdoors, is still limited. In the NanoOffice study, concentrations of nanoparticles (10–300 nm) were measured both indoors and outdoors with a 5-min time resolution at twelve office buildings in Umeå. Measurements were taken during a one-week period in the heating season and a one-week period in the non-heating season. The measuring equipment SMPS 3938 was used for indoor measurements, and DISCmini was used for outdoor measurements. The NP concentrations were highest in offices close to a bus terminal and lowest in offices near a park. In addition, a temporal effect appeared, usually with higher concentrations of nanoparticles found during daytime in the urban background area, whereas considerably lower nanoparticle concentrations were often present during nighttime. Infiltration of nanoparticles from the outdoor air into the indoor air was also common. However, the indoor/outdoor ratios (I/O ratios) of NPs showed large variations between buildings, seasons, and time periods, with I/O ratios in the range of 0.06 to 0.59. The reasons for high indoor infiltration rates could be NP emissions from adjacent outdoor sources. We could also see particle growth since the indoor NPs were, on average, almost twice as large as the NPs measured outdoors. Despite relatively low concentrations of NPs in the urban background air during nighttime, they could rise to very high daytime concentrations due to local sources, and those particles also infiltrated the indoor air.

Techno-Economic Assessment of Battery Electric Trains and Recharging Infrastructure Alternatives Integrating Adjacent Renewable Energy Sources

Battery electric multiple units (BEMU) are an effective path towards a decarbonized regional rail transport on partly electrified rail lines. As a means of sector coupling, the BEMU recharging energy demand provided through overhead line islands can be covered from decentralized renewable energy sources (RES). Thus, fully carbon-free electricity for rail transport purposes can be obtained. In this study, we analyze cost reduction potentials of efficient recharging infrastructure positioning and the feasibility of covering BEMU energy demand by direct-use of locally produced renewable electricity. Therefore, we set up a model-based approach which assesses relevant lifecycle costs (LCC) of different trackside electrification alternatives comparing energy supply from local RES and grid consumption. The model-based approach is applied to the example of a German regional rail line. In the case of an overhead line island, the direct-use of electricity from adjacent wind power plants with on-site battery storage results in relevant LCC of EUR 173.4 M/30a, while grid consumption results in EUR 176.2 M/30a whereas full electrification results in EUR 224.5 M/30a. Depending on site-specific factors such as existing electrification and line lengths, BEMU operation and partial overhead line extension can lead to significant cost reductions of recharging infrastructure as compared to full electrification.

Redox conditions, glacio-eustasy, and the status of the Cenomanian–Turonian Anoxic Event: new evidence from the Upper Cretaceous Chalk of England

The nature of the Cenomanian–Turonian Oceanic Anoxic Event (CTOAE) and its δ13 C Excursion is considered in the light of (1) the stratigraphical framework in which the CTOAE developed in the European shelf seas, (2) conclusions that can be drawn from new detailed investigations of the Chalk succession at three locations in England, at Melton Ross and Flixton in the Northern Province where organic-rich ‘black bands’ are present, and at Dover in the Southern Province (part of the Anglo-Paris Basin) where they are absent, and (3) how these conclusion fit in with the present understanding of the CTOAE. The application of the cerium anomaly method (German and Elderfield 1990) at Dover, Melton Ross and Flixton has allowed the varying palaeoredox conditions in the Chalk Sea and its sediments to be related to the acid insoluble residues, organic carbon, δ18O (calcite), δ13C (calcite), δ13C (organic matter), Fe 2+ and Mn2+ (calcite), and P/TiO2 (acid insoluble residue). This has provided evidence that the initial stages of the δ13C Excursion in England were related to (1) a drop of sea level estimated at between 45 and 85 metres, (2) influxes of terrestrial silicate and organic detritus from adjacent continental sources and the reworking of exposed marine sediments, and (3) the presence of three cold water phases (named the Wood, Jefferies and Black) associated with the appearance of the cold-water pulse fauna during the Plenus Cold Event. Conditions in the water column and in the chalk sediment were different in the two areas. In the Northern Province, cerium-enriched waters and anoxic conditions were widespread; the δ13C pattern reflects the interplay between the development of anoxia in the water column and the preservation of terrestrial and marine organic matter in the black bands; here the CTOAE was short-lived (~0.25 Ma) lasting only the length of the Upper Cenomanian Metoicoceras geslinianum Zone. In the Southern Province, water conditions were oxic and the δ13C Excursion lasted to the top of the Lower Turonian Watinoceras devonense Zone, much longer (~1.05 Ma) than in the Northern Province. These differences are discussed with respect to (1) the Cenomanian–Turonian Anoxic Event (CTAE) hypothesis when the ocean-continent-atmosphere systems were linked, (2) limitations of chemostratigraphic global correlation, and (3) the Cenomanian–Turonian Anoxic Event Recovery (CTOAER), a new term to define the varying lengths of time it took different oceans and seas to recover once the linked ocean-continent-atmosphere system was over. The possibility is considered that glacio- eustasy (the glacial control hypothesis of Jeans et al. 1991) with the waxing and waning of polar ice sheets, in association with the degassing of large igneous provinces, may have set the scene for the development of the Cenomanian–Turonian Anoxic Event (CTAE).

Imaging of CNS Fungal Infections: Review Article

Fungal infections of the central nervous system (CNS) are usually identified in immunocompromised patients but rare in immunocompetent hosts. The clinical and imaging manifestations are mainly influenced by types of fungal pathogen and immune status of the patients. The CNS fungal infections can develop through hematogenous dissemination from primary site of infection, cerebrospinal fluid seeding, or direct extension from adjacent sources of infection. Fungal infections can result in meningitis, meningoencephalitis, cerebritis, granuloma, or abscess formation, which imaging findings are often non-specific and difficult to distinguish from bacterial or tuberculous infection, non-infectious inflammatory disease, or even intracranial neoplasm. Vascular complications including vasculitis, cerebral infarction, or mycotic aneurysm are commonly present due to angioinvasion of fungal hyphae. In addition, some characteristic imaging features of fungal infections can be identified by computed tomography (CT) or magnetic resonance imaging (MRI), such as intracavitary projections in fungal abscesses and gelatinous pseudocysts in cryptococcosis that could help suggest the diagnosis. Recognizing the imaging findings of common intracranial fungal infections combined with appropriate clinical setting is crucial for allowing early diagnosis and leading to early specific treatment. The present article reviewed common imaging findings of CNS fungal infections and distinct imaging features of specific pathogens. Keywords: Fungal infection, Brain abscess, Cryptococcosis, Central nervous system (CNS), Computed tomography (CT), Diffusion weighted imaging (DWI), Magnetic resonance imaging (MRI)

Machine learning approach identifies water sample source based on microbial abundance

Water quality can change along a river system due to differences in adjacent land use patterns and discharge sources. These variations can induce rapid responses of the aquatic microbial community, which may be an indicator of water quality characteristics. In the current study, we used a random forest model to predict water sample sources from three different river ecosystems along a gradient of anthropogenic disturbance (i.e., less disturbed mountainous area, wastewater discharged urban area, and pesticide and fertilizer applied agricultural area) based on environmental physicochemical indices (PCIs), microbiological indices (MBIs), and their combination. Results showed that among the PCI-based models, using conventional water quality indices as inputs provided markedly better prediction of water sample source than using pharmaceutical and personal care products (PPCPs), and much better prediction than using polycyclic aromatic hydrocarbons (PAHs) and substituted PAHs (SPAHs). Among the MBI-based models, using the abundances of the top 30 bacteria combined with pathogenic antibiotic resistant bacteria (PARB) as inputs achieved the lowest median out-of-bag error rate (9.9%) and increased median kappa coefficient (0.8694), while adding fungal inputs reduced the kappa coefficient. The model based on the top 30 bacteria still showed an advantage compared with models based on PCIs or the combination of PCIs and MBIs. With improvement in sequencing technology and increase in data availability in the future, the proposed method provides an economical, rapid, and reliable way in which to identify water sample sources based on abundance data of microbial communities.

First order born scattering away from a fluid-filled borehole

In this paper we solve the forward scattering problem in the first order Born approximation as it applies to the multipole borehole acoustic measurement configuration. This configuration consists of a multipole source and an array of multipole receivers, both deployed on a mandrel (The tool), and where the latter is axially offset from the former by a certain distance. The tool is deployed in a fluid-filled borehole, penetrating the earth formations. Assuming an arbitrary elastodynamic scatterer away from the fluid-filled borehole, we derive explicit expressions for the far-field scattered wavefield in the borehole fluid. In principle, these expressions could be used as a fast forward operator in the development of a full waveform inversion technique. Subsequently, to further our understanding, we derive analytical expressions for the borehole fluid scattered pressure at ‘small’ source-receiver offsets, and where the scatterer is represented by a Heaviside step change in elastodynamic formation properties, having an arbitrary orientation relative to the borehole axis. Our expressions apply to tools having a multipole source and receiver of order n. Such a source/receiver consists of 2n sources/receivers, located on the circumference of the tool and azimuthally separated from one another by π/n radians. All sources may be fired with equal polarity or adjacent sources may be fired with alternate polarity. In the latter case we compare our analytical solution with 3-D finite difference simulations. We do this for the practically relevant dipole (n = 1) and quadrupole (n = 2) excitation, for the (specular) PP, SVSV and SHSH borehole acoustic scattered pressure contributions. We obtain excellent results as long as the elastodynamic contrast between scatterer and embedding is small (<30%).

Aerosol Trends during the Dusty Season over Iran

This study assessed the aerosol climatology over Iran, based on the monthly data of aerosol optical depth (AOD) derived from the reanalysis-based Modern Era Retrospective Analysis for Research and Applications (MERRA-2) and the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS). In addition, sea level pressure, wind speed, temperature, relative humidity, precipitation, and soil moisture from the ERA5 reanalysis dataset were applied to investigate the climate-related effects on temporal AOD changes. Our analysis identified positive and negative AOD trends during 2000–2010 and 2010–2018, respectively, which are likely linked to aeolian dust changes. The dust-driven AOD trends were supported by changes in the Ångström exponent (AE) and fine mode fraction (FMF) of aerosols over Iran. During the early period (2000–2010), results of AOD-meteorology correlation analyses suggest reduced soil moisture, leading to increased dust emissions, whereas our results suggest that during the later period (2010–2018) an increase of soil moisture led to decreased AOD levels. Soil moisture appears to be a key factor in dust mobilization in the region, notably in southwestern Iran, being influenced by adjacent mineral dust sources. These phenomena were affected by large-scale sea level pressure transformations and the associated meteorology in the preceding winter seasons. Using a multiple linear regression model, AOD variability was linked to various meteorological factors in different regions. Our results suggest that climatic variations strongly affect the dust cycle, with a strong dependence on wintertime conditions in the region.

BUNKERING IN UKRAINIAN PORTS

The market of bunkering services forms one of the most important segments of world trade in oil products. In fact, the bunker market provides the work of the entire shipping industry, the share of which in world GDP is growing steadily, and by 2018 was estimated at 10 to 20%. Currently, fuel bunkering is a problem for Ukrainian seaports. Over 15 years, the annual volume of bunkering in Ukrainian ports has decreased tenfold. In Ukraine there are necessary coastal bases in Kherson, Nikolaev, other places. Bunker companies can easily find the right number of bunkers on the market for service in our ports. The volume of the world bunker market is characterized by huge and constantly growing needs of the world navy in material and technical supply of fuel of the vessels of the most different function in scales of the World ocean. The determining factor of regional demand for bunkering is the intensity of vessel traffic. Demand volumes depend primarily on the number of calls to local ports, the scale of port activity, tonnage turnover, the geography of sea routes in the region, the proximity of busy shipping routes and the service of transit flows. In addition, the availability of infrastructure (technical, organizational, information) and adjacent sources of competitive fuel supply at the prices of local refineries (refineries), as well as a range of services, quality of service, traditional procurement, customer confidence. The largest bunker centers in terms of bunker fuel sales per year are Singapore, Fujairah, Rotterdam, Hong Kong, Busan, Piraeus, Antwerp, Kaohsiung, Suez Canal, Panama Canal, Houston and Gibraltar. When organizing the flight according to two schemes, two ports for bunkering were considered: Istanbul and the Pivdenny. As a result of calculations in two directions, it can be concluded that Ukrainian ports are attractive for bunkering ships in technological and economic terms. Therefore, when changing the design scheme of the bunker in the ports of Ukraine, you can get some benefits. Both carriers and bunker companies may be interested in this.

Natural Amalgam of Gold in Placers of the Ebelyakh Area -Indicator of Tectono-Fluid Activation (North-Eastern Siberian Platform)

The results of studying the typomorphic features of placer gold in the unique diamond-bearing placers of the Ebelakh river basin (Anabar diamond-bearing region) are given. Detailed study of the morphology, micro-relief of the surface and internal structure of the gold and photographing was performed using a scanning electron microscope JEOLJSM-6480LV. The gold fineness was determined using the Camebax-Micro microanalyzer and the JEOL OXFORD INCA-sight energy spectrometer. The internal structure of native gold was studied by etching gold in mounted thin sections using a proven method, using a reagent: HCl + HNO3 + FeCl3 × 6H2O + CrO3 + thiourea + water. It is determined that, modern placer occurrences were formed mainly due to the redeposition of fine high-grade gold from ancient gold-bearing intermediate sources. At the same time, in the placer of the Kamenisty creek a natural amalgam of gold is discovered, which is an aggregate consisting of several cemented rounded gold particles of small size (-0.25 mm) of various morphology. The cement is superimposed medium-grade gold with Hg content of up to 13.3%. Its internal structure is porous, and zoning is noted due to the uneven distribution of Hg. The surface of mercury gold is characterized by a brain-like microsculpture. Along with this, in some placers of the studied area, it was possible to find small (>0.2 mm) gold particles with a specific surface with the thinnest (first microns) fringe of mercury (ртутистого) gold. Obviously, these are single grains of the disintegrated aggregates of auro amalgam. We also found gold particles in an aluminosilicate film of variable Al, Si, K, Fe composition, and the smallest (1-2 microns) mineral phases of gold, sphalerite, galena, zincite and zinc-containing iron are identified on this film. It is assumed that natural amalgamation of placer gold occurred as a result of migration of mercury-containing gold-bearing hydrothermas on fault zones during tectonomagmatic activation. Based on the above-mentioned, it is assumed that there are adjacent sources of supply - low-temperature hydrothermal ore occurrences confined to the faults and formed as a result of tectonomagmatic activation processes. This proposition is confirmed by the identification of hydrothermal-metasomatic formations of K-spar-quartz-pyrite composition with disseminated gold-sulfide mineralization on the studied territory. The similarity of geological conditions of localization and the material composition of apocarbonate hydrothermal-metasomatic formations of the Ebelyakh area with the gold-bearing rocks of the Central Aldan ore district allow to estimate positively the prospects for their further study.

Wide‐viewing integral imaging display using rectangular light sources

AbstractWe propose a wide‐viewing integral imaging display. It consists of an organic light‐emitting diode, a barrier array, and a liquid crystal panel. The organic light‐emitting diode generates the rectangular light sources, and the liquid crystal panel displays the elemental images. The barriers are introduced to separate adjacent rectangular light sources and corresponding elemental images. Lights emitting from the rectangular light sources only illuminate the corresponding elemental images. The horizontal viewing angle and the luminance are both enhanced by increasing the horizontal width of the point light source. A prototype of the proposed integral imaging display is developed, and the experiment results agree well with the theory.

Multi-source aliasing suppression for distributed fiber acoustic sensing with directionally coherent enhancement technology

Distributed fiber acoustic sensing (DAS) can detect almost all disturbances along the sensing fiber and is widely applied. However, the signals from multiple adjacent disturbance sources are superimposed, according to the sensing principle. A directionally coherent enhancement technology is demonstrated for DAS to suppress multi-source aliasing in air. In preliminary works, two situations are considered for feasibility verification. The submerged weak target signal is effectively extracted from strong broadband noise, and two different same-frequency signals from two sources are separately rebuilt with the same detected signal. As far as we know, this is the first time that the directionally coherent enhancement is proposed for DAS and the multi-source aliasing is suppressed. This technique will help DAS find new important foreground in acoustic detection of large-scale plants with many similar noisy devices, including discharge detection in high voltage substations and acoustic emission flaw detection in mechanical factories.

Stratigraphy and facies architecture of the Neoproterozoic syn- and inter-eruptive succession: An example from Gabal El Urf, Northeastern Desert, Egypt

A new integrated stratigraphic, sedimentological and geochemical study was carried out on the Gabal El Urf deposits to clarify their facies architecture, sequence stratigraphic framework, and evolutionary stages. The Gabal El Urf in the Northeastern Desert of Egypt is a well-preserved example of the Neoproterozoic volcano-sedimentary deposits. It comprises inter- and syn-eruptive facies that were generated by diverse depositional processes including debris flows, sheet floods, lacustrine flood flows, and pyroclastic ash falls/density currents. These facies correspond to alluvial fan, aeolian -fluvial, lacustrine, and pyroclastic facies associations that are arranged in four depositional cycles. They reveal variations in accommodation to sediment supply (A/S) ratio. Unconformities and lithofacies assemblages define six stages of volcanism and sedimentation and three unconformity-bounded tectonic sequences that should be allied to tectonic subsidence and basin uplift. These sequences may be subdivided in Low-Accommodation Systems Tracts (LAST) having negative A/S (A/S ratio close to zero) and High-Accommodation Systems Tracts (HAST) with fluctuation in A/S ratio between zero and +1. Sequences 1 and 3 are characterized by clast-supported conglomerates and pyroclastics, overlain by fluvial sand bodies and debris flow deposits, respectively denoting a LAST (positive A/S ratio close to zero). Sequence 2 is marked by pyroclastic ash fall facies at the base, passing to lacustrine deposits that are interlayered with fan-delta conglomerates at the top, defining a HAST (A/S ratio >1). The defined sequences are superimposed by thick fissure-fed ignimbrites which are capped by a co-ignimbritic breccia lag deposits with concentrated pyroclastic fountains. Clastic petrofacies of the El Urf succession indicate an adjacent miscellaneous rock sources involving volcanic, plutonic, and metamorphic terrains during the chief sedimentation processes in rift-related paleotectonic regime. The low to moderate magnitude of the CIA and PIA together with low SiO2/Al2O3 ratio indicate sediment recycling and moderate weathering of the protolith near uplifted basin flank(s) under dominant semi-arid to arid conditions. The development of the El Urf basin is akin to the post-amalgamation Ediacaran volcano-sedimentary basins that are widely distributed in the northern part of the Arabo-Nubian Shield, and is a key tectono-stratigraphic marker for the Cryogenian-Ediacaran shift along a major unconformity surface.

PLSMS model for restoration of the details concealed by light sources in nighttime hazed image

In the popular atmospheric scattering model applied to image dehazed, the scatter from the adjacent light sources on the camera sensor which has degraded the image quality is neglected, especially when some artificial light sources exist. Therefore, in the dehazing results, the light sources are always much brighter than those in the original image in order to enhance the majority details in the dark regions, which causes the details around the light sources to be obscured. We propose a novel image restoration model mainly based on point light source multiple scattering theory. An observed hazed image can be described as a linear combination of light being reflected from an imaged object itself and its multiple scattering component. The restoration quality of the artificial light sources and details around them may be improved by suppressing the multiple scattering which can be simulated by an APSF function. The key of our model is to find the appropriate APSF kernels by analysis and some experiments. Comparisons and evaluations of our restoration results with those from popular algorithms show that ours is better in details and colors recovery in dealing with light sources in nighttime hazed images.

Theoretical and experimental analysis of temperature distribution during full tooth groove form grinding

Abstract A calculation model of grinding temperature during full tooth groove form grinding (FTGFG) was established through the simplification of the three-dimensional (3D) heat conduction process and based on the theoretical analysis of the transient moving heat source temperature field. The proposed model calculated the grinding temperature distribution of the gear surface and also described the coupling effect of two adjacent grinding heat sources at the junction of the tooth groove. Based on the grinding principle and the contact geometry relationship between the formed grinding wheel and the workpiece, the distributions of grinding parameters, grinding wheel geometry parameters, the actual contact arc length between the grinding wheel and the workpiece, tangential grinding force, and the heat partition to the workpiece were analyzed. A 3D non-uniform heat flux distribution model was also developed based on the actual tangential grinding force distribution, the linear velocity distribution of the grinding wheel, the heat partition ratio along the cross-section of the tooth groove, and the triangular heat flux model in the direction of the contact arc for the contact zone during FTGFG. Finally, a test method for form grinding temperature measurement was designed, and the theoretical model was verified by experimental results. Test results revealed that the temperature distribution on the tooth groove surface during form grinding was non-uniform. Due to the coupling effect of two adjacent heat sources, the temperature increased sharply, and a steep peak was formed at the flange where the bottom plane and the transition arc intersected or the transition arc and the involute intersected. A comparison between experimental and theoretical results on the ground surface and in the transverse section revealed that the analytical model had better prediction accuracy and that the relative error was within 15 %.

Evaluation of Directional Dependence of Sensitivity for Room-Temperature Magnetic Flux Sensors With Wide Sensitivity Region

Recently, the room-temperature (RT) magnetic flux sensors have begun to be applied to biomagnetic measurements. The RT sensors have a large advantage that they can be placed closer to the magnetic sources and obtain larger signals, unlike the superconducting quantum interference device (SQUID) flux sensors. However, when an RT sensor is placed closer to the sources, the dimension of the sensitivity region cannot be negligible, and the directional dependence of sensitivity should be considered to estimate the theoretical magnetic signals for magnetic source analysis. We proposed a method to evaluate the directional dependence of the sensitivity of the RT sensors in response to adjacent magnetic sources using the array of coils arranged along a circular arc. Consequently, it was revealed that a specific magnetoresistance device-based flux sensor with a certain spatial extent had the directional dependence of sensitivity with a bell-shaped profile. We also proposed the multiple sensitivity points model for the bell-shaped profile and estimated the sensitivity distribution over the sensitivity region, which is expected to be effective in improving the accuracy of the magnetic source analysis using an RT sensor array.

Black Carbon: The Concentration and Sources Study at the Nam Co Lake, the Tibetan Plateau from 2015 to 2016

We measured black carbon (BC) with a seven-wavelength aethalometer (AE-31) at the Nam Co Lake (NCL), the hinterland of the Tibetan Plateau (TP) from May 2015 to April 2016. The daily average concentration of BC was 145 ± 85 ng m−3, increasing by 50% since 2006. The seasonal variation of BC shows higher concentrations in spring and summer and lower concentrations in autumn and winter, dominated by the adjacent sources and meteorological conditions. The diurnal variation of BC showed that its concentrations peaked at 9:00–16:00 (UTC + 8), significantly related to local human activities (e.g., animal-manure burning and nearby traffic due to the tourism industry). The concentration-weighted trajectory (CWT) analysis showed that the long-distance transport of BC from South Asia could also be a potential contributor to BC at the NCL, as well as the biomass burning by the surrounding residents. The analyses of the absorption coefficient and absorption Ångström exponent show the consistency of sourcing the BC at the NCL. We suggest here that urgent measures should be taken to protect the atmospheric environment at the NCL, considering the fast-increasing concentrations of BC as an indicator of fuel combustion.