bluuebunny/crossref_metadata_2025 huggingface dataset:
Accurate Modeling of Working Normal Rake Angles and Working Inclination Angles of Active Cutting Edges and Application in Cutting Force Prediction
Authors: Li Peng , Chang Zhiyong
Published: October 2021

The normal rake angle is an important geometric parameter of a turning tool, and it directly affects the accuracy of the cutting force prediction. In this study, an accurate model of the working normal rake angle (WNRA) and working inclination angle (WIA) is presented, including variation in the cutting velocity direction. The active cutting edge of the turning tool is discretized into differential elements. Based on the geometric size of the workpiece and the position of the differential elements, the cutting velocity direction of each differential element is calculated, and analytical expressions for the WNRA, WIA, and working side cutting edge angle are obtained for each differential element. The size of the workpiece is found to exert an effect on the WNRA and WIA of the turning tool. The WNRA and WIA are used to predict the cutting force. A good agreement between the predicted and experimental results from a series of turning experiments on GH4169 with different cutting parameters (cutting depth and feed rate) demonstrates that the proposed model is accurate and effective. This research provides theoretical guidelines for high-performance machining.
Design and Fabrication of a Microfluidic Chip for Particle Size-Exclusion and Enrichment
Authors: Yang Luxia , Ye Tian , Zhao Xiufeng , Hu Taotao , Wei Yanlong
Published: October 2021

Based on the size of particles, a microfluidic chip integrating micro particles capture, controlled release and counting analysis was designed and fabricated in this paper. The chip is composed of a polydimethylsiloxane (PDMS) cover sheet and a PDMS substrate. The PDMS substrate is made of a sample inlet, microfluidic channels, a micropillar array, a three-dimensional (3D) focusing channel, and a sample outlet. The chip was fabricated by the multistep SU-8 lithography and PDMS molding method in this study. The micropillar array and channels in the chip can be molded in one step and can be replicated multiple times, which reduces the production cost and increases the practicability of the chip. Using a homemade electromagnetic drive device, the detection function of the chip was tested using a deionized water solution containing 22 μm polyethylene particles. The results showed that under the action of electromagnetic force, the chip enriched polyethylene particles; when the electromagnetic force disappeared, the enriched polyethylene particles were released by injecting buffer solution, and it was looked at as new sample solution. The flow rate of the sample solution and the sheath flow solution (deionized water) was injected into the three-dimensional focusing channel at a flow rate ratio of 1:4, and the polyethylene particles sample solution was focused, which could be used for the counting and analysis of polyethylene particles. The work of this paper can provide a reference for the subsequent detection of circulating tumor cells (CTCs).
Process Intensification of Chemical Exchange Method for Boron Isotope Separation Using Micro-Channel Distillation Technology
Authors: Tang Yin , Zheng Yongjie , Tian Jingzhi , Sun Jing
Published: October 2021

A micro-channel distillation device was used for the process intensification method to separate boron isotopes, 10B and 11B. Three-dimensional (3D) printing technology was introduced to manufacture the micro-channel device, which used the chemical exchange method with anisole as the donor to separate the boron isotopes. This device was tested in total reflux mode, and the height of an equivalent theoretical plate of the micro-channel distillation equipment was reduced to 1.56 cm. The accurate control of pressure and temperature, as well as the flow rate of the complex, were factors that affected separation ability. Thus, for process intensification, this micro-channel distillation device can be operated horizontally and connected in series into similar modules to effectively improve separation efficiency and reduce the size of the equipment.
Challenges for Pulsed Laser Deposition of FeSe Thin Films
Authors: Obata Yukiko , Karateev Igor A. , Pavlov Ivan , Vasiliev Alexander L. , Haindl Silvia
Published: October 2021

Anti-PbO-type FeSe shows an advantageous dependence of its superconducting properties with mechanical strain, which could be utilized as future sensor functionality. Although superconducting FeSe thin films can be grown by various methods, ultrathin films needed in potential sensor applications were only achieved on a few occasions. In pulsed laser deposition, the main challenges can be attributed to such factors as controlling film stoichiometry (i.e., volatile elements during the growth), nucleation, and bonding to the substrate (i.e., film/substrate interface control) and preventing the deterioration of superconducting properties (i.e., by surface oxidization). In the present study, we address various technical issues in thin film growth of FeSe by pulsed laser deposition, which pose constraints in engineering and reduce the application potential for FeSe thin films in sensor devices. The results indicate the need for sophisticated engineering protocols that include interface control and surface protection from chemical deterioration. This work provides important actual limitations for pulsed laser deposition (PLD) of FeSe thin films with the thicknesses below 30 nm.
The Design and Implementation of a High-Precision Positioner Fixture
Authors: Zhao Xuesen , Tan Rongkai , Wang Zhe , Zou Xicong , Hu Zhenjiang , Sun Tao
Published: October 2021

In this paper, a novel positioner fixture with a high repeated positioning accuracy and a high stiffness is proposed and investigated. A high-precision end-toothed disc is used to achieve the high repeated positioning accuracy of the designed positioner fixture. The mathematical models of the cumulative error of the tooth pitch, the tooth alignment error and the error of the tooth profile half-angle of the end-toothed disc are analyzed. The allowable tolerance values of the cumulative error of the tooth pitch, the tooth alignment error and the error of the tooth profile half-angle of the end-toothed disc are given. According to the theoretical calculation results, a prototype positioner fixture is fabricated and its repeated positioning accuracy and stiffness are tested. The test results indicate that the stiffness of the proposed positioner fixture is 1050.5 N/μm, which is larger than the previous positioner fixtures of the same type. The repeated positioning accuracy of the proposed positioner fixture in the x, y and z directions are ±0.48 μm, ±0.45 μm and ±0.49 μm, respectively, which is significantly higher than the previous positioner fixtures.
Electric Field Induced Electrorotation of 2D Perovskite Microplates
Authors: Zhou Ruifu , Hong Daobiao , Gao Siyu , Gu Yu , Liu Xuhai
Published: October 2021

High precision-controlled movement of microscale devices is crucial to obtain advanced miniaturized motors. In this work, we report a high-speed rotating micromotor based on two-dimensional (2D) all-inorganic perovskite CsPbBr3 microplates controlled via alternating-current (AC) external electric field. Firstly, the device configuration with optimized electric field distribution has been determined via systematic physical simulation. Using this optimized biasing configuration, when an AC electric field is applied at the four-electrode system, the microplates suspended in the tetradecane solution rotate at a speed inversely proportional to AC frequency, with a maximum speed of 16.4 × 2π rad/s. Furthermore, the electrical conductivity of CsPbBr3 microplates has been determined in a contactless manner, which is approximately 10−9–10−8 S/m. Our work has extended the investigations on AC electric field-controlled micromotors from 1D to 2D scale, shedding new light on developing micromotors with new configuration.
Pan-Genome Analysis of Effectors in Korean Strains of the Soybean Pathogen Xanthomonas citri pv. glycines
Authors: Kang In-Jeong , Kim Kyung Seok , Beattie Gwyn A. , Yang Jung-Wook , Sohn Kee Hoon , Heu Sunggi , Hwang Ingyu
Published: October 2021

Xanthomonas citri pv. glycines is a major pathogen of soybean in Korea. Here, we analyzed pathogenicity genes based on a comparative genome analysis of five Korean strains and one strain from the United States, 8ra. Whereas all six strains had nearly identical profiles of carbohydrate-active enzymes, they varied in diversity and number of candidate type III secretion system effector (T3SE) genes. The five Korean strains were similar in their effectors, but differed from the 8ra strain. Across the six strains, transcription activator-like effectors (TALEs) showed diverse repeat sizes and at least six forms of the repeat variable di-residue (RVD) sequences, with differences not correlated with the origin of the strains. However, a phylogenetic tree based on the alignment of RVD sequences showed two distinct clusters with 17.5 repeats, suggesting that two distinct 17.5 RVD clusters have evolved, potentially to adapt Xcg to growth on distinct soybean cultivars. The predicted effector binding elements of the TALEs fell into six groups and were strongly overlapping in sequence, suggesting evolving target specificity of the binding domains in soybean cultivars. Our findings reveal the variability and adaptability of T3SEs in the Xcg strains and enhance our understanding of Xcg pathogenicity in soybean.
Independence of a Marine Unicellular Diazotroph to the Presence of NO3−
Authors: Rabouille Sophie , Randall Benjamin , Talec Amélie , Raimbault Patrick , Blasco Thierry , Latifi Amel , Oschlies Andreas
Published: October 2021

Marine nitrogen (N2) fixation was historically considered to be absent or reduced in nitrate (NO3−) rich environments. This is commonly attributed to the lower energetic cost of NO3− uptake compared to diazotrophy in oxic environments. This paradigm often contributes to making inferences about diazotroph distribution and activity in the ocean, and is also often used in biogeochemical ocean models. To assess the general validity of this paradigm beyond the traditionally used model organism Trichodesmium spp., we grew cultures of the unicellular cyanobacterium Crocosphaera watsonii WH8501 long term in medium containing replete concentrations of NO3−. NO3− uptake was measured in comparison to N2 fixation to assess the cultures’ nitrogen source preferences. We further measured culture growth rate, cell stoichiometry, and carbon fixation rate to determine if the presence of NO3− had any effect on cell metabolism. We found that uptake of NO3− by this strain of Crocosphaera was minimal in comparison to other N sources (~2–4% of total uptake). Furthermore, availability of NO3− did not statistically alter N2 fixation rate nor any aspect of cell physiology or metabolism measured (cellular growth rate, cell stoichiometry, cell size, nitrogen fixation rate, nitrogenase activity) in comparison to a NO3− free control culture. These results demonstrate the capability of a marine diazotroph to fix nitrogen and grow independently of NO3−. This lack of sensitivity of diazotrophy to NO3− suggests that assumptions often made about, and model formulations of, N2 fixation should be reconsidered.
Reversal of Polymicrobial Biofilm Tolerance to Ciprofloxacin by Blue Light plus Carvacrol
Authors: Li Yongli , Wu Mei X.
Published: October 2021

Chronic wound infections are often caused by multi-species biofilms and these biofilm-embedded bacteria exhibit remarkable tolerance to existing antibiotics, which presents huge challenges to control such infections in the wounds. In this investigation, we established a polymicrobial biofilm composed of P. aeruginosa, S. aureus, K. pneumoniae, and A. baumannii. We tested a cocktail therapy comprising 405-nm blue light (BL), carvacrol (Ca), and antibiotics on the multispecies biofilm. Despite the fact that all strains used to form the biofilm were susceptible to ciprofloxacin (CIP) in planktonic cultures, the biofilm was found to withstand ciprofloxacin as well as BL-Ca dual treatment, mainly because K. pneumoniae outgrew and became dominant in the biofilm after each treatment. Strikingly, when ciprofloxacin was combined with BL-Ca, the multispecies biofilms succumbed substantially and were eradicated at an efficacy of 99.9%. Mechanistically, BL-Ca treatment increased membrane permeability and potentiated the anti-biofilm activity of ciprofloxacin, probably by facilitating ciprofloxacin’s entrance of the bacteria, which is particularly significant for K. pneumoniae, a species that is refractory to either ciprofloxacin or BL-Ca dual treatment. The results suggest that bacterial membrane damage can be one of the pivotal strategies to subvert biofilm tolerance and combat the recalcitrant multispecies biofilms.
Genetic Predisposition to Persistent Human Papillomavirus-Infection and Virus-Induced Cancers
Authors: Espinoza Helen , Ha Kim T. , Pham Trang T. , Espinoza J. Luis
Published: October 2021

Human papillomaviruses (HPVs) are the most common sexually transmitted pathogens worldwide and among the more than 200 identified HPV types, approximately 15 high risk (HR-HPV) types are oncogenic, being strongly associated with the development of cervical cancer, anogenital cancers and an increasing fraction of head and neck squamous cell carcinomas (HNSCC). HPV-associated cervix cancer accounts for 83% of HPV-attributable cancers, and more than two-thirds of those cases occur in developing countries. Despite the high frequency of HPV infections, in most cases, the virus is cleared by the host immune response and only a small proportion of infected individuals develop persistent infections that can result in malignant transformation, indicating that other elements, including biological, genetic and environmental factors may influence the individual susceptibility to HPV-associated cancers. Previous studies have quantified that heritability, in the form of genetic variants, common in the general population, is implicated in nearly 30% of cervical cancers and a large number of studies conducted across various populations have identified genetic variants that appear to be associated with genes that predispose or protect the host to HPV infections thereby affecting individual susceptibility to HPV-associated cancers. In this article, we provide an overview of gene association studies on HPV-associated cancers with emphasis on genome-wide association study (GWAS) that have identified novel genetic factors linked to HPV infection or HPV-associated cancers.
Bioavailable Nutrients (N and P) and Precipitation Patterns Drive Cyanobacterial Blooms in Missisquoi Bay, Lake Champlain
Authors: Celikkol Sukriye , Fortin Nathalie , Tromas Nicolas , Andriananjamanantsoa Herinandrianina , Greer Charles W.
Published: October 2021

Anthropogenic activities release large amounts of nitrogen (N) and phosphorus (P) nutrients into the environment. Sources of nutrients include surface and sub-surface runoffs from agricultural practices with the application of chemical fertilizers and manure as well as combined sewer overflows (CSOs). Nutrient runoffs contribute to the eutrophication of aquatic ecosystems and enhance the growth of cyanobacteria. Precipitation is an important driving force behind the runoff of nutrients from agricultural fields into surrounding water bodies. To understand the dynamics between nutrient input, precipitation and cyanobacterial growth in Missisquoi Bay, Lake Champlain (Quebec), one location in Pike River (a major tributary into the bay) and four locations in Missisquoi Bay were monitored from April to November in 2017 and 2018. Biweekly water samples were analyzed using chemical methods and high-throughput sequencing of 16S rRNA gene amplicons. High concentrations of N and P were typically measured in April and May. Three major spikes in nutrient concentrations were observed in early and mid-summer as well as early fall, all of which were associated with intense cumulative precipitation events of 40 to 100 mm within 7 days prior to sampling. Despite the high concentrations of nutrients in the spring and early summer, the cyanobacterial blooms appeared in mid to late summer as the water temperature increased. Dolichospermum sp. was the major bloom-forming cyanobacterium during both summers. A second intense bloom event of Microcystis was also observed in the fall (October and November) for both years. Variation in the cyanobacteria population was strongly associated with inorganic and readily available fractions of N and P such as nitrites and nitrates (NOx), ammonia (NH3) and dissolved organic phosphorus (DOP). During blooms, total Kjeldahl nitrogen (TKN) and total particulate phosphorus (TPP) fractions had a substantial influence on total nitrogen (TN) and total phosphorus (TP) concentrations, respectively. The abundance of bacteria involved in the metabolism of nitrogen compared to that of phosphorus revealed the importance of nitrogen on overall microbial dynamics as well as CB formation in the bay. Our findings emphasize the combined influence of precipitation events, temperature and several bioavailable fractions of nitrogen and phosphorus on cyanobacterial bloom episodes.
Intraspecies Variation in Tetrahymena rostrata
Authors: Watt Anne , Young Neil , Haites Ruth , Dunse Kerry , Russell Derek , Billman-Jacobe Helen
Published: October 2021

Two distinct isolates of the facultative parasite, Tetrahymena rostrata were compared, identifying and utilising markers that are useful for studying clonal variation within the species were identified and utilised. The sequences of mitochondrial genomes and several nuclear genes were determined using Illumina short read sequencing. The two T. rostrata isolates had similar morphology. The linear mitogenomes had the gene content and organisation typical of the Tetrahymena genus, comprising 8 tRNA genes, 6 ribosomal RNA genes and 45 protein coding sequences (CDS), twenty-two of which had known function. The two isolates had nucleotide identity within common nuclear markers encoded within the histone H3 and H4 and small subunit ribosomal RNA genes and differed by only 2–4 nucleotides in a region of the characterised actin genes. Variation was observed in several mitochondrial genes and was used to determine intraspecies variation and may reflect the natural history of T. rostrata from different hosts or the geographic origins of the isolates.
Complete Life Cycle of Trypanosoma thomasbancrofti, an Avian Trypanosome Transmitted by Culicine Mosquitoes
Authors: Fialová Magdaléna , Santolíková Anežka , Brotánková Anna , Brzoňová Jana , Svobodová Milena
Published: October 2021

Avian trypanosomes are cosmopolitan and common protozoan parasites of birds; nevertheless, knowledge of their life cycles and vectors remains incomplete. Mosquitoes have been confirmed as vectors of Trypanosoma culicavium and suggested as vectors of T. thomasbancrofti; however, transmission has been experimentally confirmed only for the former species. This study aims to confirm the experimental transmission of T. thomasbancrofti to birds and its localization in vectors. Culex pipiens were fed on blood using four strains of T. thomasbancrofti, isolated from vectors and avian hosts; all strains established infections, and three of them were able to develop high infection rates in mosquitoes. The infection rate of the culicine isolates was 5–28% for CUL15 and 48–81% for CUL98, 67–92% for isolate OF19 from hippoboscid fly, while the avian isolate PAS343 ranged between 48% and 92%, and heavy infections were detected in 90% of positive females. Contrary to T. culicavium, trypanosomes were localized in the hindgut, where they formed rosettes with the occurrence of free epimastigotes in the hindgut and midgut during late infections. Parasites occurred in urine droplets produced during mosquito prediuresis. Transmission to birds was achieved by the ingestion of mosquito guts containing trypanosomes and via the conjunctiva. Bird infection was proven by blood cultivation and xenodiagnosis; mature infections were present in the dissected guts of 24–26% of mosquitoes fed on infected birds. The prevalence of T. thomasbancrofti in vectors in nature and in avian populations is discussed in this paper. This study confirms the vectorial capacity of culicine mosquitoes for T. thomasbancrofti, a trypanosome related to T. avium, and suggests that prediuresis might be an effective mode of trypanosome transmission.
Open System Re-Os Isotope Behavior in Platinum-Group Minerals during Laterization?
Authors: Aiglsperger Thomas , González-Jiménez José M. , Proenza Joaquín A. , Galí Salvador , Longo Francisco , Griffin William L. , O’Reilly Suzanne Y.
Published: October 2021

In this short communication, we present preliminary data on the Re-Os isotopic systematics of platinum-group minerals (PGM) recovered from different horizons in the Falcondo Ni-laterite in the Dominican Republic. The results show differences in the Os-isotope composition in different populations of PGM: (i) pre-lateritic PGM yield 187Os/188Os varying from 0.11973 ± 0.00134 to 0.12215 ± 0.00005 (2σ uncertainty) whereas (ii) lateritic PGM are more radiogenic in terms of 187Os/188Os (from 0.12390 ± 0.00001 to 0.12645 ± 0.00005; 2σ uncertainty). We suggest that these differences reflect the opening of the Re-Os system in individual grains of PGM during lateritic weathering. The implications of these results are twofold as they will help to (1) elucidate the small-scale mobility of noble metals in the supergene setting and therefore the possible formation of PGM at these very low temperatures, (2) better refine the Os-isotopic datasets of PGM that are currently being used for defining dynamic models of core–mantle separation, crustal generation, and fundamental plate-tectonic processes such as the opening of oceans.
Salinity Monitoring at Saline Sites with Visible–Near-Infrared Spectral Data
Authors: Li Wei , Liu Jing , Bao Nisha , Mao Xinqi , Mao Yachun , Fu Yanhua , Cao Wang , Huang Jiaqi , Zhao Zhanguo
Published: October 2021

To address the global phenomenon of the salinisation of large land areas, a quantitative inversion model of the salinity of saline soils and soil visible–near-infrared (NIR) spectral data was developed by considering saline soils in Zhenlai County, Jilin Province, China as the research object. The original spectral data were first subjected to Savitzky–Golay (SG) smoothing, multiplicative scattering correction (MSC) pre-processing, and a combined transformation technique. The pre-processed spectral data were then analysed to construct the difference index (DI), ratio index (RI), and normalised difference index (NDI), and the Spearman rank correlation coefficient (r) between these three spectral indices and the salt content in the samples was calculated, while a combined spectral index (r > 0.8) was eventually selected as a sensitive spectral index. Finally, a quantitative inversion model for the salinity of saline soils was developed, and the model’s accuracy was evaluated based on partial least squares regression (PLSR), the random forest (RF) algorithm, and the radial basis function (RBF) neural network algorithm. The results indicated that the inversion of soil salt content using the selected combination of spectral indices based on the RBF neural network algorithm was the most effective, with the prediction model yielding an R2 value of 0.950, a root mean square error (RMSE) of 1.014, and a relative percentage deviation (RPD) of 4.479, which suggested a good prediction effect.
Potential Uranium Migration within the Geochemical Gradient of the Opalinus Clay System at the Mont Terri
Authors: Hennig Theresa , Kühn Michael
Published: October 2021

Transport properties of potential host rocks for nuclear waste disposal are typically determined in laboratory or in-situ experiments under geochemically controlled and constant conditions. Such a homogeneous assumption is no longer applicable on the host rock scale as can be seen from the pore water profiles of the potential host rock Opalinus Clay at Mont Terri (Switzerland). The embedding aquifers are the hydro-geological boundaries, that established gradients in the 210 m thick low permeable section through diffusive exchange over millions of years. Present-day pore water profiles were confirmed by a data-driven as well as by a conceptual scenario. Based on the modelled profiles, the influence of the geochemical gradient on uranium migration was quantified by comparing the distances after one million years with results of common homogeneous models. Considering the heterogeneous system, uranium migrated up to 24 m farther through the formation depending on the source term position within the gradient and on the partial pressure of carbon dioxide pCO2 of the system. Migration lengths were almost equal for single- and multicomponent diffusion. Differences can predominantly be attributed to changes in the sorption capacity, whereby pCO2 governs how strong uranium migration is affected by the geochemical gradient. Thus, the governing parameters for uranium migration in the Opalinus Clay can be ordered in descending priority: pCO2, geochemical gradients, mineralogical heterogeneity.
Study on the 3D Sedimentary Characteristics of Sandstone Type Uranium Reservoir Based on 3D Seismic Attribute
Authors: Sun Zhangqing , Liu Yaguang , Han Fuxing , Zhang Fengjiao , Ou Xiyang , Cao Minqiang , Lei Anguai , Yang Songlin , Liu Mingchen , Gao Zhenghui
Published: October 2021

It is of great significance to quickly obtain the sedimentary characteristics of sandstone type uranium reservoir for guiding prospecting sandstone type uranium deposits. In order to solve this problem, a method based on the extraction and optimization of 3D seismic attributes is proposed. The target stratum of the uranium reservoir is accurately located by using the gamma and acoustic logging data together. The well seismic calibration for the uranium reservoir is carried out by making full use of the logging and seismic data. The high-density fine horizon tracking is implemented for the top, bottom, and obvious adjacent interfaces of the target stratum. Various seismic attributes along the target interface are extracted using stratigraphic slices. Analyzing the consistency between the results obtained by various seismic attributes and drilling data, the one that can best characterize the sedimentary characteristics of the target uranium reservoir is selected as the optimal seismic attribute. The sedimentary and its evolutionary characteristics of the target uranium reservoir are obtained by extracting the above optimal seismic attribute. A case study shows that we can obtain the 3D sedimentary characteristics of the target uranium reservoir fast and efficiently using the method based on the 3D seismic attribute. They can be used for providing important reference information for the exploration of sandstone type uranium deposits.
Three-Dimensional Structural Analysis of Ferromanganese Nodules from the Western North Pacific Ocean Using X-ray Computed Tomography
Authors: Nakamura Kentaro , Terauchi Daiki , Shimomura Ryo , Machida Shiki , Yasukawa Kazutaka , Fujinaga Koichiro , Kato Yasuhiro
Published: October 2021

The three-dimensional layered growth structure of 934 ferromanganese nodule samples collected from dives in the Pacific Ocean around Minamitorishima Island was assessed using X-ray computed tomography (X-ray CT) to elucidate their growth history. The thickness of the layered structure measured in three orthogonal directions showed that the ferromanganese nodules grew equally in all directions regardless of shape and size. Based on differences in CT numbers, a layered structure was subdivided into sublayers I, II, III, and IV, which corresponded to petrological features. The nodules were then classified as Types I, II, III, and IV according to whether they had sublayers I, I and II, I–III, or I–IV, respectively. Correlations between the total thickness of the layers and the number of sublayers indicated that both represented the relative age of the nodules. Nodules with all these types were recovered from most of the sampling sites, and histograms of the total layer thickness at each dive site showed several peaks. These findings indicated that the initiation of nodule growth was intermittent, rather than simultaneous. Three distinct thickness peaks were found at many sites throughout the study area, suggesting that at least three nodule initiation events covering hundreds of kilometers initiated the growth of ferromanganese nodules.
Application of a Wide-Field Electromagnetic Method for Hot Dry Rock Exploration: A Case Study in the Gonghe Basin, Qinghai, China
Authors: Tan Hui , Ling Fan , Guo Zhenwei , Li Jie , Liu Jiawei
Published: October 2021

Hot dry rock (HDR) is a geothermal resource with a high temperature that is widely distributed and has good potential as a clean and renewable energy source. To determine underground electrical structures and to predict granite reservoir distributions, the wide-field electromagnetic (WFEM) method has been applied to explore deep mineral resources and has advantages such as explorations at greater depths and at high resolutions. In this study, a WFEM investigation was carried out for HDR exploration in Gonghe Basin within Qinghai Province. Six parallel survey lines, each spaced apart by 1 km, were designed for WFEM data acquisition. After data processing and inversion, we mapped the subsurface resistivity distribution and divided the inversion resistivity of HDR in the Qiabuqia area into four layers. From the WFEM results, we inferred the location of HDRs, which was verified using drilling wells. HDRs were found at a depth between 3200 m and 3705 m in the well. Furthermore, with the calibration of drilling well GR1, we provided the relationship between temperature and inversion resistivity. From this relationship, the exploration areas with mining potential can be determined.
The Effect of Curing under Applied Stress on the Mechanical Performance of Cement Paste Backfill
Authors: Zhao Yue , Taheri Abbas , Karakus Murat , Deng An , Guo Lijie
Published: October 2021

After placing the Cement Paste Backfill (CPB) slurry in mined cavities underground, during the setting and hardening processes, the weight and hydrostatic pressure of the upper-layer CPB slurry applies an axial load over the bottom-layer CPB materials, which is called the self-consolidation of CPB slurry. Due to this phenomenon, the mechanical properties of in situ CPB could be considerably different from laboratory results. Hence, it is crucial to understand the effect of self-consolidation behaviour on the mechanical properties of backfill material. This paper presents an experimental study on the impact of axial applied stress (As) during curing, which represents the various self-consolidation conditions and curing times on the mechanical properties of CPB material prepared using the tailings of a copper mine in South Australia and a newly released commercially manufactured cement called Minecem (MC). A curing under pressure apparatus (CPA) is designed to cure CPB samples under axial applied stress. The equipment can apply and measure axial load during curing and measure the passive lateral stress due to axial load which represents the horizontal stresses at a certain depth of CPB stope on the retaining structure. The prepared samples with axially applied pressure during curing were tested under uniaxial and triaxial compressive loading conditions. Microstructural tests by scanning electron microscopy (SEM) were also used to study the fabric evolution in response to various applied stresses during curing. Overall, the increase in As during curing leads to higher resultant CPB peak strength and stiffness under uniaxial and triaxial compression tests. For instance, a sample cured under 3.6 MPa axial load for 28 days demonstrates a uniaxial compressive strength (UCS) value of five times more than a sample cured under atmospheric curing conditions. Passive lateral stress was measured during the curing period and was representative of underground barricade stress. Furthermore, during curing, the axial applied stress changed the initial CPB pore structure after placement. With the increase in applied stress, the stress compressed CPB samples at the macroscale, leading to much smaller pores or cracks prior to the hydration process. At an early stage, the increase in UCS due to axial applied stress mainly arises from a dense microstructure caused by the compression of tailings and cement particles. With the increase in curing time, the observation also shows that a CPB matrix with fewer pore spaces may improve the hydration progress; hence, the influence of axial applied stress becomes more pronounced in long-term UCS.
Determination of Gold Particle Characteristics for Sampling Protocol Optimisation
Authors: Dominy Simon , Platten Ian , Glass Hylke , Purevgerel Saranchimeg , Cuffley Brian
Published: October 2021

Sampling, sample preparation, and assay protocols aim to achieve an acceptable estimation variance, as expressed by a relatively low nugget variance compared to the sill of the variogram. With gold ore, the typical heterogeneity and low grade generally indicate that a large sample size is required, and the effectiveness of the sampling protocol merits attention. While sampling protocols can be optimised using the Theory of Sampling, this requires determination of the liberation diameter (dℓAu) of gold, which is linked to the size of the gold particles present. In practice, the liberation diameter of gold is often represented by the most influential particle size fraction, which is the coarsest size. It is important to understand the occurrence of gold particle clustering and the proportion of coarse versus fine gold. This paper presents a case study from the former high-grade Crystal Hill mine, Australia. Visible gold-bearing laminated quartz vein (LV) ore was scanned using X-ray computed micro-tomography (XCT). Gold particle size and its distribution in the context of liberation diameter and clustering was investigated. A combined mineralogical and metallurgical test programme identified a liberation diameter value of 850 µm for run of mine (ROM) ore. XCT data were integrated with field observations to define gold particle clusters, which ranged from 3–5 mm equivalent spherical diameter in ROM ore to >10 mm for very high-grade ore. For ROM ore with clusters of gold particles, a representative sample mass is estimated to be 45 kg. For very-high grade ore, this rises to 500 kg or more. An optimised grade control sampling protocol is recommended based on 11 kg panel samples taken proportionally across 0.7 m of LV, which provides 44 kg across four mine faces. An assay protocol using the PhotonAssay technique is recommended.
Petrogenesis of the Early Cretaceous Hongshan Complex in the Southern Taihang Mountains: Constraints from Element Geochemistry, Zircon U-Pb Geochronology and Hf Isotopes
Authors: Chu Xiaolei , Sun Jinggui , Sun Fanting , Mei Yanxiong , Liu Yang , Men Lanjing , Zhao Keqiang , Zhang Xiaotian
Published: October 2021

The Hongshan complex, located in the southern part of the Taihang Mountains in the central part of the North China Craton, consists of syenite stocks (including fine-grained biotite aegirine syenite, medium-grained aegirine gabbro syenite, coarse-grained aegirine gabbro syenite, syenite pegmatite, and biotite syenite porphyry), with monzo-diorite and monzo-gabbro dikes. This paper presents zircon U-Pb ages and Hf isotope data and whole-rock geochemical data from the Hongshan complex. LA–ICP-MS zircon U–Pb age from the fine-grained biotite aegirine syenite, monzo-diorite, and monzo-gabbro are 129.3 ± 2.0 Ma, 124.8 ± 1.3 Ma, and 124.1 ± 0.9 Ma, respectively, indicating their emplacement in the Early Cretaceous when the North China Craton was extensively reactivated. The monzo-diorite and monzo-gabbro have low SiO2 contents (48.94–57.75 wt%), total alkali contents (5.2–9.4 wt%), and εHf (t) values of −22.3 to −18.4 and are enriched in MgO (4.0–8.2 wt%), Al2O3 (14.3–15.8 wt%), light rare earth elements (LREEs) and large ion lithophile elements (LILEs). Interpretation of elemental and isotopic data suggests that the magma of monzo-diorite and monzo-gabbro were derived from partial melting of the enriched lithospheric mantle metasomatized by slab-derived hydrous fluids. Syenites with high alkali (K2O + Na2O = 9.4–13.0 wt%) and Sr contents (356–1737 ppm) and low Yb contents (0.94–2.65 ppm) are enriched in Al (Al2O3 = 16.4–19.1 wt%), but depleted in MgO (0.09–2.56 w%), Cr (Avg = 7.16 ppm), Co (Avg = 6.85 ppm) and Ni (Avg = 9.79 ppm), showing the geochemical features of adakitic rocks associated with thickened lower crust. Combining zircon 176Hf/177Hf ratios of 0.282176 to 0.282359, εHf(t) values of −18.3 to −11.8 and εNd (t) values of −11.1 to −8.2, we conclude that the syenite magma was derived from the mixing of the thickened lower crust and the enriched lithospheric mantle magma. These magma processes were controlled by Paleo-Pacific plate subduction and resulted in the destruction and thinning of the central North China Craton.
Concentration, Spatial Distribution and Potential Ecological Risk of Heavy Metals in Stream Sediments of the Misiones Province, Argentina
Authors: Zhao Dongjie , Chen Yuming , Zhang Weibo , Chen Xifeng , Chen Xiufa , Zhang Fuliang
Published: October 2021

One hundred and twenty-eight stream sediment samples were collected in the Misiones province of Argentina by the low-density geochemical mapping project of the China Geological Survey. The analyzed data were used to study the concentration, spatial distribution, local pollution level and potential ecological risk of eight heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb and Zn) by factor analysis, geoaccumulation index (Igeo), enrichment factor (EF) and the Hakanson’s potential ecological risk index (Eir and RI) methods. Results showed that the background values (median) of those elements were 2.97 ppm, 0.13 ppm, 212.60 ppm, 322.53 ppm, 0.013 ppm, 64.42 ppm, 12.58 ppm, and 198.85 ppm, respectively. Except for Hg, the contents of other elements were higher than the abundance of continental crust. The spatial distribution of Cu and Zn in stream sediments were consistent, while that of other elements were different. The factor analysis results implied that Cd, Cr, Cu, Ni and Zn were mainly affected by geological background and inherited the characteristics of regional parent rocks. Furthermore, Pb was not only controlled by natural conditions but also related to human activities, while As and Hg represented the anthropogenic sources, and their concentrations were affected by human activities. The results of Igeo and EF told us that Cu was heavily polluted in stream sediments; Pb and Zn were largely mildly polluted; As, Cr, Cd, Ni and Hg were mostly nonpolluted. The ecological risks were ordered as As > Cu > Cd > Pb > Hg > Cr > Ni > Zn. In general, the potential ecological risk of heavy metals in the Misiones province was low, but As and Cu also have a high ecological risk at some sampling points, which should be considered.
Emplacement and Segment Geometry of Large, High-Viscosity Magmatic Sheets
Authors: Schmiedel Tobias , Burchardt Steffi , Mattsson Tobias , Guldstrand Frank , Galland Olivier , Palma Joaquín , Skogby Henrik
Published: October 2021

Understanding magma transport in sheet intrusions is crucial to interpreting volcanic unrest. Studies of dyke emplacement and geometry focus predominantly on low-viscosity, mafic dykes. Here, we present an in-depth study of two high-viscosity dykes (106 Pa·s) in the Chachahuén volcano, Argentina, the Great Dyke and the Sosa Dyke. To quantify dyke geometries, magma flow indicators, and magma viscosity, we combine photogrammetry, microstructural analysis, igneous petrology, Fourier-Transform-Infrared-Spectroscopy, and Anisotropy of Magnetic Susceptibility (AMS). Our results show that the dykes consist of 3 to 8 mappable segments up to 2 km long. Segments often end in a bifurcation, and segment tips are predominantly oval, but elliptical tips occur in the outermost segments of the Great Dyke. Furthermore, variations in host rocks have no observable impact on dyke geometry. AMS fabrics and other flow indicators in the Sosa Dyke show lateral magma flow in contrast to the vertical flow suggested by the segment geometries. A comparison with segment geometries of low-viscosity dykes shows that our high-viscosity dykes follow the same geometrical trend. In fact, the data compilation supports that dyke segment and tip geometries reflect different stages in dyke emplacement, questioning the current usage for final sheet geometries as proxies for emplacement mechanism.
Decay Detection in an Ancient Column with Combined Close-Range Photogrammetry (CRP) and Ultrasonic Tomography
Authors: Casula Giuseppe , Fais Silvana , Cuccuru Francesco , Bianchi Maria Giovanna , Ligas Paola , Sitzia Alessandro
Published: October 2021

This study presents the integrated application of a few non-destructive techniques, i.e., Close Range Photogrammetry (CRP), and low frequency (24 kHz) ultrasonic tomography complemented by petrographical analysis. The aim here is to assess the conservation state of a Carrara marble column in the Basilica of San Saturnino, which is part of a V-VI century Palaeo Christian complex in the city of Cagliari (Italy). The high resolution 3D modelling of the studied artifact was computed starting from the integration of proximal sensing techniques, such as CRP based on the Structure from Motion (SfM) technique, which provided information on the geometrical anomalies and reflectivity of the investigated marble column surface. The inner parts of the studied body were inspected successfully in a non-invasive way by computing the velocity pattern of the ultrasonic signal through the investigated materials, using 3D ultrasonic tomography. The latter was optimally designed based on the 3D CRP analysis and the locations of the source and receiver points were detected as accurately as possible. The integrated application of in situ CRP and ultrasonic techniques provided a full 3D high resolution model of the investigated artifact, which made it possible to evaluate the material characteristics and its degradation state, affecting mainly the shallower parts of the column. The 3D visualisation improves the efficiency, accuracy, and completeness of the interpretative process of data of a different nature in quite easily understood displays, as well as the communication between different technicians.
Synthesis and Photocatalytic Activity of TiO2/CdS Nanocomposites with Co-Exposed Anatase Highly Reactive Facets
Authors: Du Yi-en , Niu Xianjun , He Xinru , Hou Kai , Liu Huiling , Zhang Caifeng
Published: October 2021

In this work, TiO2/CdS nanocomposites with co-exposed {101}/[111]-facets (NH4F-TiO2/CdS), {101}/{010} facets (FMA-TiO2/CdS), and {101}/{010}/[111]-facets (HF-TiO2/CdS and Urea-TiO2/CdS) were successfully synthesized through a one-pot solvothermal method by using [Ti4O9]2− colloidal solution containing CdS crystals as the precursor. The crystal structure, morphology, specific surface area, pore size distribution, separation, and recombination of photogenerated electrons/holes of the TiO2/CdS nanocomposites were characterized. The photocatalytic activity and cycling performance of the TiO2/CdS nanocomposites were also investigated. The results showed that as-prepared FMA-TiO2/CdS with co-exposed {101}/{010} facets exhibited the highest photocatalytic activity in the process of photocatalytic degradation of methyl orange (MO), and its degradation efficiency was 88.4%. The rate constants of FMA-TiO2/CdS was 0.0167 min−1, which was 55.7, 4.0, 3.7, 3.5, 3.3, and 1.9 times of No catalyst, CdS, HF-TiO2/CdS, NH4F-TiO2/CdS, CM-TiO2, Urea-TiO2/CdS, respectively. The highest photocatalytic activity of FMA-TiO2/CdS could be attributed to the synergistic effects of the largest surface energy, co-exposed {101}/{010} facets, the lowest photoluminescence intensity, lower charge-transfer resistance, and a higher charge-transfer efficiency.
Aspergillus oryzae-Fermented Wheat Peptone Enhances the Potential of Proliferation and Hydration of Human Keratinocytes through Activation of p44/42 MAPK
Authors: Hahm Kyung Man , Park See-Hyoung , Oh Sae Woong , Kim Ji Hye , Yeom Hyun Sook , Lee Hye Ja , Yang Seoyeon , Cho Jae Youl , Park Jin Oh , Lee Jongsung
Published: October 2021

Identifying materials contributing to skin hydration, essential for normal skin homeostasis, has recently gained increased research interest. In this study, we investigated the potential benefits and mechanisms of action of Aspergillus oryzae-fermented wheat peptone (AFWP) on the proliferation and hydration of human skin keratinocytes, through in vitro experiments using HaCaT cell lines. The findings revealed that compared to unfermented wheat peptone, AFWP exhibited an improved amino acid composition, significantly (p < 0.05) higher DPPH scavenging capability and cell proliferation activity, and reduced lipopolysaccharide-induced NO production in RAW 264.7 cells. Furthermore, we separated AFWP into eleven fractions, each ≤2 kDa; of these, fraction 4 (AFW4) demonstrated the highest efficacy in the cell proliferation assay and was found to be the key component responsible for the cell proliferation potential and antioxidant properties of AFWP. Additionally, AFW4 increased the expression of genes encoding natural moisturizing factors, including filaggrin, transglutaminase-1, and hyaluronic acid synthase 1–3. Furthermore, AFW4 activated p44/42 MAPK, but not JNK and p38 MAPK, whereas PD98059, a p44/42 MAPK inhibitor, attenuated the beneficial effects of AFW4 on the skin, suggesting that the effects of AFW4 are mediated via p44/42 MAPK activation. Finally, in clinical studies, AFW4 treatment resulted in increased skin hydration and reduced trans-epidermal water loss compared with a placebo group. Collectively, these data provide evidence that AFW4 could be used as a potential therapeutic agent to improve skin barrier damage induced by external stresses.
Recent Advances and Applications of Plant-Based Bioactive Saponins in Colloidal Multiphase Food Systems
Authors: Xu Mengyue , Wan Zhili , Yang Xiaoquan
Published: October 2021

The naturally occurring saponins exhibit remarkable interfacial activity and also possess many biological activities linking to human health benefits, which make them particularly attractive as bifunctional building blocks for formulation of colloidal multiphase food systems. This review focuses on two commonly used food-grade saponins, Quillaja saponins (QS) and glycyrrhizic acid (GA), with the aim of clarifying the relationship between the structural features of saponin molecules and their subsequent self-assembly and interfacial properties. The recent applications of these two saponins in various colloidal multiphase systems, including liquid emulsions, gel emulsions, aqueous foams and complex emulsion foams, are then discussed. A particular emphasis is on the unique use of GA and GA nanofibrils as sole stabilizers for fabricating various multiphase food systems with many advanced qualities including simplicity, ultrastability, stimulability, structural viscoelasticity and processability. These natural saponin and saponin-based colloids are expected to be used as sustainable, plant-based ingredients for designing future foods, cosmetics and pharmaceuticals.