bluuebunny/crossref_metadata_2025 huggingface dataset:
Epidemiological Profile of the Victims of Sexual Violence Treated at a Referral Center in Southern Brazil
Authors: Santarem Michelle Dornelles , Marmontel Mariane , Pereira Nathália Lima , Vieira Letícia Becker , Savaris Ricardo Francalacci
Published: September 2020

Objective To characterize the sociodemographic profile of women victims of sexual violence treated at a university hospital in southern Brazil.

Method The present cross-sectional study included all female victims of sexual violence who attended the sexual violence unit at the Hospital de Clínicas de Porto Alegre (HCPA, in the Portuguese acronym) from April 18, 2000 to December 31, 2017. Data were extracted from the electronic record of the patients and stored in a standardized questionnaire database with epidemiological aspects of the victim, the perpetrators and the type of aggression. Statistical analysis was performed using the chi-squared test for trend and descriptive statistics with 95% confidence interval (CI).

Results During the length of the study, 711 women victims of sexual violence were treated. The mean age of the patients was 24.4 (±10) years old (range from 11 to 69 years old) and most of the victims were white (77.4%), single (75.9%) and sought care at the unit within 72 hours after the occurrence (80.7%). In most cases, violence was exerted by a single perpetrator (87.1%), who was unknown in 67.2% of cases. Victims < 19 years old showed a higher risk of not using contraception (relative risk [RR] = 2.7; 95% CI = 1.9–3.6).

Conclusion Most victims of sexual violence were treated within 72 hours of the occurrence. The majority of these victims were white and young, and those < 19 years old had a higher risk of not using contraception and to know the sexual perpetrator.
Neurological Problems in COVID-19 Pandemic
Authors: Saini Shiv Kumar , Anand Kuljeet Singh , Juneja Abhishek , Mahajan Rakesh Kumar
Published: September 2020

Coronavirus disease 2019 (COVID-19) is a potentially severe acute respiratory infection caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This outbreak, which emerged in Wuhan city, rapidly spread throughout China and has now become a global public health concern. SARS-CoV-2 is a highly pathogenic and transmissible virus. Common clinical manifestations of COVID-19 include fever, dry cough, shortness of breath, muscle ache, headache, and confusion. Currently, there is no confirmed effective therapeutic strategy for COVID-19 because the pathological mechanism is poorly understood. In addition to the respiratory system involvement, recent evidence has shown that SARS-CoV-2 can affect other organ systems including nervous, vascular, digestive, and urinary system. Various neurological complications have also been described in various studies. Nervous system involvement in the case of SARS-CoV-2 is explained by direct neuro invasion, immune mechanism, and other systemic factors. Neurological complications due to SARS-CoV-2 include both central and peripheral nervous system involvement. Central nervous system complications range from mild headache to seizures, encephalitis, myelitis, and acute cerebrovascular accidents. Peripheral nervous system complications range from vague muscle pains to Guillain–Barré syndrome. This article briefly discusses the various neurological and mental health issues related to COVID-19.
Molecular dynamics study on scattering characteristics of nitrogen molecules from platinum surface by molecular beam method
Authors: Yu Hang , Zhang Ye , Yang Fan , Li Hua
Published: September 2020

Rarefied gas flow has received wide attention due to the booming of micro/nano-electromechanical systems and aerospace engineering. Under such rarefied conditions, the frequency of intermolecular collisions is sharply reduced, so the impacts of interactions between gas molecules and the wall surface on flow states become non-negligible. Owing to the complexity of theoretical research and the poor reproducibility of experimentation, molecular dynamics simulation has developed into an effective method to study the interplay between gases and solid surfaces. In this study, molecular dynamics simulations on the scattering process of nitrogen molecules from a platinum surface are conducted in a three-dimensional system. The dependences of scattering angle distributions and momentum/energy variations on the incident velocity, angles, and surface roughness are obtained. The results of this paper are not only an attempt to reveal the mechanisms of gas–surface interactions but can also be used as necessary reference data for the development of appropriate gas–surface interaction models.
Chronic pain: good management of practical pain control strategies is associated with being older, more health activated and having better mental health
Authors: Budge Claire , Taylor Melanie , Mar Materoa , Hansen Chiquita , Fai Folole
Published: September 2020

ABSTRACT
INTRODUCTIONChronic pain affects a large proportion of the adult population and people in pain need to learn how to manage it in order to maintain quality of life.
AIMThis study aimed to examine how well people with long-term conditions make use of self-management strategies to control their pain, and to identify personal attributes associated with a higher degree of success.
METHODSPeople with chronic pain who participated in the first phase of a longitudinal long-term conditions study in the MidCentral region made up the study sample (N=326, response rate 21%). They completed a questionnaire by mail or online, which included items on pain management, general health, patient activation, experiences with general practice and demographics.
RESULTSPain control strategies were managed fairly well overall. Taking pain medication and avoiding caffeine, alcohol, heavy meals and exercise before bed were managed best, whereas sleep, relaxation breathing and remaining socially active were managed least well. A multiple regression analysis found higher scores on patient activation, self-rated overall pain management at home, mental health and older age (≥75 years) to be associated with better management.
DISCUSSIONThis study identified pain control strategies that are managed well, and less well, outside of a specific intervention. Results highlight topics for discussion in consultations and identify areas where general practice could provide better self-management support, such as sleep and exercise. Better overall pain control strategy management was most strongly associated with patient activation; that is, a combination of knowledge, skills and confidence to manage health and health care that is amenable to intervention. Improving the level of activation in people with long-term conditions may enhance their use of pain control strategies.
A decade-long study on mayfly emergence patterns
Authors: Vilenica Marina , Ivković Marija
Published: September 2020

Mayfly assemblage structure, microhabitat preference and emergence patterns were studied over a decade in two types of karst freshwater habitats, namely, a spring and two tufa barriers. Mayfly adults were collected using pyramidal emergence traps. A total of nine species was recorded. Tufa barriers had a higher species richness but a lower abundance than did the spring. All sites were dominated by species typical of the rhithral zone. The spring had the highest share of grazers, whereas gatherers (collectors and filter feeders) dominated at tufa barriers, with minimal changes through the years. Mayfly abundance at the spring was higher in years with a higher discharge. The opposite was recorded for tufa barriers, which could be related to drift and food availability. Mayflies emerged from the spring between March and November, most probably being triggered by the photoperiod. Emergence from tufa barriers was seasonal and related to changes in water temperature. Some species exhibited typical central European emergence patterns, whereas, in some others, certain discrepancies were recorded. Several taxa showed preference towards emergence from a particular microhabitat. The present study showed that for fine ecological data on aquatic insects, long-term studies are essential.
Hybridisation experiments between freshwater prawns Macrobrachium amazonicum and M. pantanalense (Decapoda: Palaemonidae), and the effects of geographical isolation
Authors: Nogueira Caio Santos , Pantaleão João Alberto Farinelli , Costa Rogerio Caetano
Published: September 2020

The freshwater prawns Macrobrachium amazonicum and M. pantanalense are phylogenetically closely related. The present study analysed the occurrence of copulation between these two species. Specimens of M. amazonicum were collected from the Tietê River in Cambaratiba (SP), whereas M. pantanalense specimens were collected from the Lagoa Baíazinha, in Miranda (MS). Six different experimental groups were used, MA♂×MP♀, MA♀×MP♂ (interspecifc), MA♂×MA♀, MP♂×MP♀ (intraspecific), MA♀ and MP♀ (individualised; MA=M. amazonicum and MP=M. pantanalense). The incubation times of the ovigerous females were monitored in all experiments. Some females from all experimental groups were randomly selected and had their oocytes photographed to verify the occurrence of embryonic development. No larvae hatched in the interspecific experimental groups, whereas, in intraspecific groups, almost all experiments (95%) presented larval hatching. The incubation period differed significantly (P<0.001) between the intraspecific groups and all the other experimental groups, but not between each other (P>0.05). The interspecific and individualised groups showed no significant (P>0.05) difference between them. In addition, oocytes from the interspecific experimental groups did not present characteristics of embryonic development. Our results suggest that M. pantanalense and M. amazonicum populations do not copulate, which corroborates the proposal of recent speciation.
Fire, forests and fauna (The 2020 Krebs Lecture)
Authors: Lindenmayer David
Published: September 2020

This article discusses some of the key themes on wildfires in forests and their effects on fauna that I explored in the 2020 Krebs lecture at the University of Canberra. The lecture examined my personal perspectives on such topics as (1) climate change and fire, (2) the role of hazard reduction burning in mitigating house loss from wildfires, (3) how logging can elevate the risks of high-severity wildfire, (4) the ways in which the structure and age of a forest at the time it is burnt has marked impacts on post-fire recovery, (5) the ecological damage caused by post-fire (salvage) logging, and (6) aspects of post-fire species recovery. Perspectives on these topics are informed largely by long-term work in the wet forests of Victoria and the coastal forests and woodlands in the Jervis Bay Territory and neighbouring southern New South Wales. Some key policy and land management responses to wildfires are outlined, including (1) the urgent need to tackle climate change, (2) better targeting of hazard reduction burning close to human infrastructure, (3) the removal of conventional logging and post-fire (salvage) logging from native forests, (4) the substantial expansion of the old growth forest estate, and (5) the establishment of dedicated long-term monitoring to gather the empirical data needed to quantify responses to wildfires.
Spatial correlates of forest and land fires in Indonesia
Authors: Tan Z. D. , Carrasco L. R. , Taylor D.
Published: September 2020

Biomass fires in Indonesia emit high levels of greenhouse gases and particulate matter, key contributors to global climate change and poor air quality in south-east Asia. In order to better understand the drivers of biomass fires across Indonesia over multiple years, we examined the distribution and probability of fires in Sumatra, Kalimantan (Indonesian Borneo) and Papua (western New Guinea) over four entire calendar years (2002, 2005, 2011 and 2015). The 4 years of data represent years with El Niño and La Niña conditions and high levels of data availability in the study region. Generalised linear mixed-effects models and zero-inflated negative binomial models were used to relate fire hotspots and a range of spatial predictor data. Geographic differences in occurrences of fire hotspots were evident. Fire probability was greatest in mixed-production agriculture lands and in deeper, degraded peatlands, suggesting anthropogenic activities were strong determinants of burning. Drought conditions in El Niño years were also significant. The results demonstrate the importance of prioritising areas of high fire probability, based on land use and other predisposing conditions, in effective fire management planning.
Organic matter from the Chicxulub crater exacerbated the K–Pg impact winter
Authors: Lyons Shelby L. , Karp Allison T. , Bralower Timothy J. , Grice Kliti , Schaefer Bettina , Gulick Sean P. S. , Morgan Joanna V. , Freeman Katherine H.
Published: September 2020

Significance

Burn markers are observed in many records of the Cretaceous–Paleogene asteroid impact and mass extinction event. These materials could be derived from wildfires on land or from sedimentary rocks hit by the asteroid. We present a detailed record of molecular burn markers (polycyclic aromatic hydrocarbons [PAHs]) from the Chicxulub crater and in ocean sediments distant from the impact site. PAH features indicate rapid heating and a fossil carbon source and are consistent with sedimentary carbon ejected from the impact crater and dispersed by the atmosphere. Target rock-derived soot immediately contributed to global cooling and darkening that curtailed photosynthesis and caused widespread extinction. PAH evidence indicates wildfires were present but less influential on global climate and extinction.
The early Aurignacian dispersal of modern humans into westernmost Eurasia
Authors: Haws Jonathan A. , Benedetti Michael M. , Talamo Sahra , Bicho Nuno , Cascalheira João , Ellis M. Grace , Carvalho Milena M. , Friedl Lukas , Pereira Telmo , Zinsious Brandon K.
Published: September 2020

Significance

We report the remarkable discovery of an early Aurignacian occupation, ∼5,000 years older than any Upper Paleolithic site in westernmost Eurasia. The archaeological and radiocarbon data provide definitive evidence that modern humans were in western Iberia at a time when, if present at all, Neanderthal populations would have been extremely sparse. This discovery has important ramifications for our understanding of the process of modern human dispersal and replacement of Neanderthal populations. The results support a very rapid, unimpeded dispersal of modern humans across western Eurasia and support the notion that climate and environmental change played a significant role in this process.
Suspicious minds in times of crisis: determinants of Romanians’ beliefs in COVID-19 conspiracy theories
Authors: Stoica Cătălin Augustin , Umbreș Radu
Published: September 2020

The current pandemic has generated many conspiracy theories (CTs). In this paper, we investigate several determinants of COVID-19 CTs using survey data from Romania. Some of our findings are consistent with those of previous studies on other CTs: low values of social integration, open-mindedness, and analytical thinking predict conspiracy thinking as well as higher levels of collective narcissism. Other findings run counter to those of prior research on CTs. We hypothesize that this might be due to the specificity of the CTs under scrutiny and related to the Romanian context.
Analysis of the contributions of human factors and natural factors affecting the vegetation pattern in coastal wetlands
Authors: Zang Zheng , Wu Xiaowei , Niu Yun , Mao Guangxiong
Published: September 2020

Introduction
: Accurate identification of the dominant factors affecting coastal wetlands can provide a reference for vegetation rehabilitation. In this study, quantitative analysis was performed on the Yancheng coastal wetland using ANOVA and geostatistical methods.
Outcomes/other
: The results indicated that in the directions perpendicular and parallel to the coastline, the soil moisture and salinity in the study area exhibited relatively significant (p<0.05) spatial variability. Vegetation in the southern experimental zone was in a low-moisture, low-salinity ecological niche, whereas vegetation in the northern experimental zone was in a high-moisture, high-salinity ecological niche. Soil salinity exhibited higher spatial variability than soil moisture, and it was most correlated with unvegetated mudflats, followed by areas with Spartina alterniflora, Suaeda glauca, and Phragmites australis.
Discussion
: The fitting of the semivariogram showed that the nugget and sill of the ratio were relatively low (<25%) for soil moisture and salinity in the northern experimental zone and northern buffer zone, whereas these values were relatively high (>75%) for soil moisture and salinity in the southern experimental zone and southern buffer zone.
Conclusion
: Compared with the northern study area, the contribution of human disturbance to the spatial heterogeneity of soil moisture and salinity in the southern study area is higher.
TGF-β and Eomes control the homeostasis of CD8+ regulatory T cells
Authors: Mishra Shruti , Liao Wei , Liu Yong , Yang Ming , Ma Chaoyu , Wu Haijing , Zhao Ming , Zhang Xin , Qiu Yuanzheng , Lu Qianjin , Zhang Nu
Published: September 2020

In addition to Foxp3+ CD4+ regulatory T cells (CD4+ T reg cells), Foxp3− CD8+ regulatory T cells (CD8+ T reg cells) are critical to maintain immune tolerance. However, the molecular programs that specifically control CD8+ but not CD4+ T reg cells are largely unknown. Here, we demonstrate that simultaneous disruption of both TGF-β receptor and transcription factor Eomesodermin (Eomes) in T cells results in lethal autoimmunity due to a specific defect in CD8+ but not CD4+ T reg cells. Further, TGF-β signal maintains the regulatory identity, while Eomes controls the follicular location of CD8+ T reg cells. Both TGF-β signal and Eomes coordinate to promote the homeostasis of CD8+ T reg cells. Together, we have identified a unique molecular program designed for CD8+ T reg cells.
Helicobacter pylori metabolites exacerbate gastritis through C-type lectin receptors
Authors: Nagata Masahiro , Toyonaga Kenji , Ishikawa Eri , Haji Shojiro , Okahashi Nobuyuki , Takahashi Masatomo , Izumi Yoshihiro , Imamura Akihiro , Takato Koichi , Ishida Hideharu , Nagai Shigenori , Illarionov Petr , Stocker Bridget L. , Timmer Mattie S.M. , Smith Dylan G.M. , Williams Spencer J. , Bamba Takeshi , Miyamoto Tomofumi , Arita Makoto , Appelmelk Ben J. , Yamasaki Sho
Published: September 2020

Helicobacter pylori causes gastritis, which has been attributed to the development of H. pylori–specific T cells during infection. However, the mechanism underlying innate immune detection leading to the priming of T cells is not fully understood, as H. pylori evades TLR detection. Here, we report that H. pylori metabolites modified from host cholesterol exacerbate gastritis through the interaction with C-type lectin receptors. Cholesteryl acyl α-glucoside (αCAG) and cholesteryl phosphatidyl α-glucoside (αCPG) were identified as noncanonical ligands for Mincle (Clec4e) and DCAR (Clec4b1). During chronic infection, H. pylori–specific T cell responses and gastritis were ameliorated in Mincle-deficient mice, although bacterial burdens remained unchanged. Furthermore, a mutant H. pylori strain lacking αCAG and αCPG exhibited an impaired ability to cause gastritis. Thus H. pylori–specific modification of host cholesterol plays a pathophysiological role that exacerbates gastric inflammation by triggering C-type lectin receptors.
A revised solution for a sphere rolling in a vertical loop
Authors: Bertran Oscar , Riba Jordi
Published: September 2020

In this paper the classical well-known solution of the elementary problem of the sphere loop in the presence of friction is studied. Also, a modification of the problem shows a possible inaccuracy involved in the well-known solution found in many references. Finally, a revised solution of the problem is presented.
Microdosimetry-based determination of tumour control probability curves for treatments with 225Ac-PSMA of metastatic castration resistant prostate cancer
Authors: Mínguez Gabiña Pablo , Roeske John C , Mínguez Ricardo , Rodeño Emilia , Gómez de Iturriaga Alfonso
Published: September 2020

We performed Monte Carlo simulations in order to determine, by means of microdosimetry calculations, tumour control probability (TCP) curves for treatments with 225Ac-PSMA of metastatic castration resistant prostate cancer (mCRPC). Realistic values of cell radiosensitivity, nucleus size and lesion size were used for calculations. As the cell radiosensitivity decreased, the nucleus size decreased and the lesion size increased, the absorbed dose to reach a given TCP increased. The widest variations occurred with regard to the cell radiosensitivity. For the Monte Carlo simulations, in order to address a non-uniform PSMA expression, different 225Ac-PSMA distributions were considered. The effect of these different PSMA distributions resulted in small variations in the TCP curves (maximum variation of 5%). Absorbed doses to reach a TCP of 0.9 for a uniform 225Ac-PSMA distribution, considering a relative biological effectiveness (RBE) of 5, ranged between 35.0 Gy and 116.5 Gy. The lesion absorbed doses per administered activity reported in a study on treatments with 225Ac-PSMA of mCRPC ranged between 1.3 Gy MBq−1 and 9.8 Gy MBq−1 for a RBE = 5. For a 70 kg-patient to whom 100 kBq kg−1 of 225Ac-PSMA are administered, the range of lesion absorbed doses would be between 9.1 Gy and 68.6 Gy. Thus, for a single cycle of 100 kBq kg−1, a number of lesions would not receive an absorbed dose high enough to reach a TCP of 0.9.
Data-driven estimation of noise variance stabilization parameters for low-dose x-ray images
Authors: Hariharan Sai Gokul , Strobel Norbert , Kaethner Christian , Kowarschik Markus , Fahrig Rebecca , Navab Nassir
Published: September 2020

Purpose. Denoising x-ray images corrupted by signal-dependent mixed noise is usually approached either by considering noise statistics directly or by using noise variance stabilization (NVS) techniques. An advantage of the latter is that the noise variance can be stabilized to a known constant throughout the image, facilitating the application of denoising algorithms designed for the removal of additive Gaussian noise. A well-performing NVS is the generalized Anscombe transform (GAT). To calculate the GAT, the system gain as well as the variance of electronic noise are required. Unfortunately, these parameters are difficult to predict from the x-ray tube settings in clinical practice, because the system gain observed at the detector depends on the beam hardening caused by the patient. Materials and Methods. We propose a data-driven method for estimating the parameters required to carry out an NVS using the GAT. It utilizes the energy compaction property of the discrete cosine transform to obtain the NVS parameters using a robust regression approach relying on a linear Poisson-Gaussian model. The method has been experimentally validated with respect to beam hardening as well as denoising performance for different dose and scatter levels. Results. Across a range of low-dose x-ray settings, the proposed robust regression approach has estimated both system gain and electronic noise level with an average error of only 4.2%. When used to perform a GAT followed by the denoising of low-dose x-ray images, performance gains of 5% for peak-signal-to-noise ratio and 4% for structural similarity index can be obtained. Conclusion. The parameters needed to calculate the GAT can be estimated efficiently and robustly using a data-driven approach. The improved parameter estimation method facilitates a more accurate GAT-based NVS and, hence, better denoising of low-dose x-ray images when algorithms designed for additive Gaussian noise are applied.
Investigation of electrical performance and operation stability of RF-sputtered InSnZnO thin film transistors by oxygen-ambient rapid thermal annealing
Authors: Maeng Seohyun , Kim Hyunjin , Choi Gisang , Choi Youngjoon , Oh Saeroonter , Kim Jaekyun
Published: September 2020

We investigated the electrical properties and operational stability of amorphous indium-tin-zinc-oxide (a-ITZO) thin-film transistors (TFTs). We fabricated the a-ITZO TFTs using deposition by radio frequency sputtering at room temperature followed by a rapid thermal annealing (RTA) process at different temperatures and oxygen pressure (P
O2). This is a more practical annealing route compared to a conventional furnace. Based on film densification and oxygen vacancy optimization, the a-ITZO TFTs exhibited 9.8 cm2 Vs−1, 0.82 V/decade and 1.39 V, for saturation mobility, sub-threshold swing and threshold voltage, respectively. Operation stability tests and hysteresis behavior of a-ITZO TFTs suggest that oxygen vacancy concentration of a-ITZO thin films gradually decreases under higher P
O2, consequently affecting the threshold voltage and the shift seen after a gate bias stress test. This observation suggests that gate bias stress and hysteresis stability of an a-ITZO device is due to the effect of oxygen-controlled pressure in the RTA process. This a-ITZO TFTs electrical characterization qualitatively coincides with x-ray photoelectron spectroscopic analyses of oxygen vacancy concentration in a-ITZO thin films. Thus, our systematic a-ITZO thin film optimization using the oxygen-ambient RTA process is a practical basis for high-performance amorphous oxide semiconductor TFT post-annealing methods.
Electro-mechanical properties of thermoplastic polyurethane films and tubes modified by hybrid carbon nanostructures for pressure sensing
Authors: Pérez-Aranda C , Valdez-Nava Z , Gamboa F , Cauich-Rodríguez J V , Avilés F
Published: September 2020

Electrical and piezoresistive properties of hybrid nanocomposite films and tubes made of a segmented aliphatic polyurethane modified with multilayer graphene sheets (MLGSs), multiwall carbon nanotubes (MWCNTs), and hybrid mixtures of both, were investigated. Hybrid nanocomposites were fabricated at a total weight concentration (

Φ
T

) of 5 wt.%, with relative weight concentration of MLGSs with respect to MWCNTs (

Φ
R

)

of 25%, 50% and 75%. The electrical conductivity of these films is dominated by the MWCNT network, observing electrical MLGS-MWCNT collaborative effects only for

Φ
R

= 25%. Dielectric impedance spectroscopy indicates that the nanocomposites display capacitive effects at frequencies higher than tens of Hz, which is explained by interfacial polarization. The burst pressure and circumferential stiffness of internally pressurized tubes fabricated from these films is slightly higher for tubes containing only MWCNTs. The strain fields in the pressurized tubes, determined by digital image correlation, showed localized strain gradients, and the piezoresistive response of the electro-conductive tubes was nonlinear. The highest pressure sensitivity factor (4.59 kPa−1) was obtained for hybrid nanocomposite tubes with

Φ
R

= 25%.
Influence of neon seeding on the deuterium retention and surface modification of ITER-like forged tungsten
Authors: Yuan Yue , Wang Ting , Kreter Arkadi , Reinhart Michael , Terra Alexis , Möeller Sören , Cheng Long , Linsmeier Christian , Lu Guang-Hong
Published: September 2020

In order to investigate the effect of neon seeding on deuterium retention and surface modification of ITER-like forged tungsten with grains elongated perpendicular to the surface, pure and neon-seeded deuterium plasma exposures were performed in the linear plasma device PSI-2. The ion percentage of neon in the mixed plasma was around 10%. The sample temperature and deuterium ion fluence were kept at 450 K and 1 × 1026 m−2, respectively. The incident ion energy was 40 eV, just reaching the tungsten sputtering threshold for neon. Surface observations show that neon seeding leads to pronounced cracking and erosion of blister caps and a significant reduction of small blisters (<0.8 μm). This is possibly attributed to surface sputtering and the inhibitory effect of neon-induced defects on blister nucleation by hindering dislocation movements. On the other hand, neon seeding increases the total deuterium retention by ∼70% according to the thermal desorption spectroscopy (TDS) measurements. A low-temperature desorption peak (∼660 K) which should be mainly ascribed to deuterium de-trapping from dislocations is observed to be broadened and shifts towards higher temperature in the case of neon seeding, suggesting enhanced inward diffusion and trapping of deuterium. An additional deuterium release peak appears at a higher temperature (∼803 K), indicating the creation of new deuterium-traps induced by neon. A comparison of the results of nuclear reaction analysis and TDS reveals that neon seeding not only increases deuterium retention in the surface region (<7.2 μm) but also in the bulk (>7.2 μm). We ascribe the enhanced deuterium retention to the increased deuterium-traps in the top-surface induced by Ne irradiation and the vertical grain boundary configuration of the forged W promoting the inward diffusion of deuterium.
Research on the three-dimensional detection system of the rail full profile
Authors: Zhou Zhendong , Yang Haima , Liu Jin
Published: September 2020

To solve the problem of slow speed, low precision and low efficiency of manual measurement in the current inspection of rail. Based on the non-contact laser profilers, a three-dimensional detection system of the full profile of rail is proposed by using the integrated combination of four laser profilers. The top straightness of the rail is detected by two-point connection method and the bottom distortion of the rail is detected by the common-plane method. After field testing, the machine measurement accuracy of the rail height, rail head width, rail bottom width and rail waist width in both rail head and tail are 0.039, 0.037, 0.029, 0.036mm and 0.047, 0.037, 0.039, 0.042mm respectively; The distortion are 0.035 and 0.039mm respectively. Experiments show that the system can complete the measurement of rail efficiently and steadily, and improve the speed, accuracy and efficiency of measurement.
Ultra-low emission transformation of 600 MW supercritical circulating fluidized bed boilers unit
Authors: Xin Shengwei , Han Ping , Li Yingping , Zhang Peng , Duan Shoubao , Gan Zheng , Wang Hu , Du Jiajun , Hao Qianjun
Published: September 2020

With the introduction of ultra-low emission environmental protection policies in national and local coal-fired power plants, ultra-low emission transformation of coal-fired power plants is required to be carried out in an all-round way. Under this background, the first 600 MW supercritical circulating fluidized bed (SCCFB) boiler unit in the world have carried out the demonstration of the technical route of ultra-low emission transformation and the research of key technologies. By adopting limestone desulphurization and low nitrogen combustion in furnace, selective non-catalytic reduction (SNCR) technology outside furnace and the integrated desulfurization and dust removal process of flue gas circulating fluidized bed (CFB-FGD), the unit realizes the technical route of ultra-low emission, and has good investment and operation economy, which can adapt to the development trend of environmental protection in the future. The CFB-FGD and dust removal system can further improve the operation economy of the boiler by setting pre-electrostatic precipitator (pre-ESP), designing double-tower and optimizing the single-tower switching mode, optimizing the pressure margin of the induced draft fan, and adopting the coordinated desulphurization operation mode inside and outside the furnace. The research results can provide a reference for the selection of ultra-low emission transformation for 660MW ultra-supercritical CFB boiler unit.
Research on steel barrel flattened seam recognition based on machine vision
Authors: Niu Hao , Wu Bowen , Wang Qingyan , Zhu Zhisong
Published: September 2020

Aiming at the problems of low efficiency and poor accuracy in manually identifying the flattened weld seam. The method of combining machine vision technology with multi-thread and multi-process is proposed, and the detection and recognition system of flattened weld seam is designed. OTSU adaptive threshold algorithm combined with Canny operator edge detection method is used for image segmentation. The probabilistic Hough transform algorithm is used to extract straight lines to identify flattened weld seam. OpenCV function library and Python are used to implement image processing algorithm, and PyQt5 is used to design human-computer interface to monitor the status of weld seam detection in real time. Meanwhile, a processing pool for parallel processing of recognition algorithm is established, and Modbus communication and image acquisition are realized by multi-thread programming. The performance of multi-core CPU is fully utilized. The experimental results show that the system meets the design requirements, has the characteristics of small amount of calculation and accurate identification, improves the processing efficiency, and solves the practical production problems.
Strength check for production riser during dry tree unit coil tubing operations under different environmental conditions
Authors: Fu Fei , Yu Jianxing , Meng Zhanbin , Han Xiangxi
Published: September 2020

In this paper, we introduce the modelling, loads, result evaluation method and boundary for production riser strength analysis. We investigated the different result evaluation method and different boundary condition based on a real project. The strength checks for the riser coil tubing stack up system in different environmental conditions was performed by SACS Software, calculate the most critical members UC and the maximum loads at critical flange locations of the riser during the whole dry tree unit coil tubing operations. According to the corresponding specification, the analysis results show that all the values of UC less than 1 and the project meet design requirements.
Effect of coupling weight of marine diesel engine on crankshaft vibration and lubrication
Authors: Wu Limin , Li Mei , Yang Ximin , Li Liting , Liang Gang , Qiao Xinqi
Published: September 2020

Journal misalignment caused by coupling weight result in rotary unbalance. To study the unbalanced effect, based on AVL EXCITE PU software, coupled multi-body dynamics and lubrication model of a marine diesel engine had been built, and validated by engine experimental data. Based on the simulation model, vibration and bearing lubrication of crankshaft with different rear-end configuration had been discussed. The results show that the unbalance caused by rear end coupling weight of crankshaft have effect on the 1st and 2nd main bearing near flywheel, and have little effect on other main bearings. It also changes the pressure distribution of upper and lower shell, and brings edge thermal load increase. Meanwhile, it has more effect on the heat transfer to shell than to journal.
Guidance for quadriceps rehabilitation based on AnyBody
Authors: Yu Shuting , Yao Ligang , Lu Zongxing , Cai Can
Published: September 2020

This paper aims to perform an objective quantitative analysis on quadriceps rehabilitation, and investigate the muscle status in cross-over design under rehabilitation actions. Rehabilitation actions are modeled using the human body modeling software AnyBody, which can analyze the variations in the muscle activity and muscle force of the quadriceps femoris during thigh flexion. In addition, it can experimentally validate the effectiveness of the model in combination with electromyographic (EMG) signals of three quadriceps femoris muscles during different activities. According to the study results, the rehabilitation actions of the quadriceps femoris can be quantified by means of collecting EMG signals.
Experimental study on the failure of tangential anti-loose dowel of ship hydraulic fluid tubing in alternating torque and vibration environment
Authors: Wu Ruliang , Huang Shouqing , Song Chao , He Wei
Published: September 2020

The internal hydraulic fluid tubing in central shaft is a critical part of pitch adjusting paddle in the ship propulsion system. The failure of screw pairs of internal hydraulic fluid tubing will result in a loss of propulsion. This real accident has happened on a ship. In order to determine the reason for the tangential anti-loose dowel falling out from the screw pairs, 380.5h and 147h alternating torque and vibration environment tests are completed on two samples with difference of manufacturing processing. The result shows that alternating torque and vibration combined stress is the synthesis stress for the dowel falling out from dowel hole. The basic reason is the larger fit clearance between dowel and dowel hole. This clearance is suggested to be manufactured below 0.2∽0.3mm, and the value of diameter for piercing outside the dowel hole should be greater than 1.95mm.
A method to calculate the life of sliding bearings based on fatigue and wear failure considering fluid lubrication
Authors: Guo Jiacheng , Huang Shouqing , Wu Ruliang , Ye Tianyuan , Chen Zhuo
Published: September 2020

In this paper, a sliding bearing is taken as the research object to study the life simulation and calculation under conditions of a certain eccentricity, a radius clearance, inlet and outlet pressures, a radial load, and taking into account fatigue and wear failure modes. For a calculation case when the eccentricity is 0.6, the average radius gap is 0.05 mm, the inlet pressure is 2 MPa, the outlet pressure is 0.1 MPa, and the radial load is 5000 N. The calculated fatigue life is infinite and the wear life is 7.1×104 revolutions. This paper focuses on providing a method for quantitatively estimating the life of sliding bearings.
Calculation and analysis on braided carbon/carbon composite pull-through fastener threads load distribution
Authors: Bian Tianya , Guo Wantao , Li Xiang
Published: September 2020

Braided carbon/carbon composites are widely used in the aerospace field due to their superior performance. However, because braided carbon/carbon composite materials have anisotropy characteristics, the distribution of screw loads in the fastener connection structure will differ from that of metal. In view of the particularity of the braided carbon/carbon composite fasteners’ connection, this paper obtains the theoretical results of the load distribution of screw teeth through the homogenization of stiffness and establishes a finite element model for comparative verification. The trend of finite element results is the same as that of theoretical calculation results which can provide guidance for the engineering design of carbon/carbon composite fastener.
Tool path active design for tooth modification of face-hobbed spiral bevel gears
Authors: Guo Wenchao , Mao Shimin , Yang Yu
Published: September 2020

An advanced design and manufacturing method called tool path active design for face-hobbed spiral bevel gears is mainly discussed in this paper. The method bases on the forming mechanism of extended epicycloids and utilizes an integrated cutter head without tilting, meanwhile, all its controlled parameters can be directly calculated according to the given meshing performances and modified conditions. Starting with the cutting principle of face-hobbing method, a tooth flank mending plan of altering tool path is developed, which detailed expressions are also given in functions. Then, the meshing performances which are used to determine the modification parameters are introduced and their formulas are also derived. Finally, the proposed method is validated by a numerical example of tooth contact analysis for a face-bobbed hypoid gear pair. As a further explanation, a numerical example of tooth contact analysis is done to validate the feasibility of the proposed method.
Analysis of 500kV composite insulator fracture fault
Authors: Liu Hui , Yang Tianshu , Zhou Chao , Jia Ran , Zhang Yang , Qi Zhao
Published: September 2020

This paper describes the fracture of composite insulator string of B phase on Tower 72 of 500kV line. A series of tests have been taken on the core rod and sheath to analyze the causation of the accident, including hydrophobicity test, dissection analysis, dye penetration, SEM and FTIR. It is found that the surface of the fault insulator is chalked, and its hydrophobicity is reduced. The interface between the epoxy resin matrix and silicone rubber sheath has completely failed. Epoxy resin matrix has been degraded, and partial discharge on the surface of core rod accelerates this process. The main chain of Si-O and side chain of Si-C in silicone rubber molecule are severely broken, and the surface of the umbrella is aging. It is concluded that the interface failure between sheath and core rod is the main cause of crisp fracture. Partial discharge at high voltage end and weak interface between glass fiber and epoxy resin matrix result in the development of degradation channels. Pollution and chalking on the surface of umbrella also explain part of the reason.
Research on 3D reconstruction technology of microscopic pore defects in cast steel
Authors: Yan Huadong , Zhou Xuewen
Published: September 2020

Affected by the production process, microscopic pore defects are inevitably distributed in steel castings. The existence of microscopic defects affects the macroscopic mechanical properties of steel castings. The numerical analysis of finite element model with microscopic pore defects is one of the effective ways to reveal the influence of microscopic defects on failure and fracture of steel castings. However, the spatial morphology of microscopic pore defects in cast steel is extremely complex, so the traditional CAE modeling method cannot meet the accuracy requirements. This article was inspired by the idea of reverse modeling in the medical field. Based on the 3D X-ray tomography data of G20Mn5N cast steel specimens, 3D models of microscopic pore defects with complex spatial morphology were reconstructed. Finite element analysis was performed in representative volume elements (RVE) model to study the effect of microscopic pore defects characteristics on the mechanical properties of cast steel.
Dynamic behavior analysis of radial hydraulically damped bushing based on FSI FEA method
Authors: Li Lin , Zeng Xiangkun , Feng Xiaolin
Published: September 2020

Nonlinear dynamic performances of hydraulically damped bushings (HDBs) can be characterized with two terms, dynamic stiffness and loss angle. In this paper, dynamic characteristics of a RHDB are estimated based on FSI FEA methods. Dynamic performances of the RHDB by FSI FEA method are precise. Obviously, FSI FEA method proposed in this paper can be effectively used to investigate and optimize dynamic characteristics of a RHDB, and also further to solve FSI problems of other component with hydraulic damping properties in the design stage.
Research on CIGRE benchmark model and improved DC control strategy
Authors: Yan Han , Liu Ke , Wang Xuan , Che Keshan , Ding Yujie , Yang Wenli
Published: September 2020

The safe and stable operation of the HVDC transmission system greatly depends on the control system. The DC control system realizes a series of control strategies such as constant-current, constant-voltage, and constant-extinction angle control by controlling the trigger phase. The CIGRE Benchmark model is often used as a standard test model for research, but it is usually necessary to improve in actual project. First of all, taking the CIGRE Benchmark model as the research object, the DC control mode and basic control functions are introduced systematically. On this basis, the improved control strategy is studied. At the same time, PSCAD / EMTDC simulation software is used to build an improved control system model. The transient response of CIGRE Benchmark and improved control system is simulated and analyzed. Furthermore, the control mode conversion and control system response under different control strategies are studied.
ISAR imaging and cross-range scaling of maneuvering targets using the scaled transform
Authors: Chen Jie , Pan Xiaogang , Xie Zhiming , Zhang Kunlun , Li Yaoyu
Published: September 2020

In this paper, a novel method based on the scaled transform is proposed for the ISAR imaging and cross-range scaling of a maneuvering target with uniform rotating acceleration. Firstly, the cross-range signals in each range cell can be modeled as multiple chirp signals. The scaled transform is utilized to eliminate the coupling with the slow time and lag time in the time-dependent autocorrelation function of multiple chirp signals. Then the 2-D accumulation plane can be obtained by the 2-D FFT and the cross-range profile can be obtained by a projection from the 2-D accumulation plane to the azimuth dimension. Meanwhile, the initial frequency and chirp rate of each scatterer can be estimated by the corresponding perk in the 2-D accumulation plane. Finally, the rotating motion parameters are estimated by the least square method and the cross-range scaling is performed. Simulation results prove the effectiveness of the proposed method.
Mixed Weibull distribution model of DC protection system based on entropy weight method
Authors: Wang Ting , Chen Kun , Zhang Kanjun , Du Zheng’an , Li Jun , Dai Di
Published: September 2020

By analyzing the blocking event of DC converter station of the State Grid Corporation in recently ten years, it can be concluded that the sampling system failure, secondary circuit fault, board fault, host fault, etc. of the protection system caused more than 10% of the DC system blockings, which have seriously threatened the normal operation of DC system. Towards this end, this paper makes a statistical analysis of the operation defects of high-voltage direct current (HVDC) transmission protection in Hubei Company in the past five years. A mixed Weibull distribution model method based on entropy weight method is proposed. By using this method, the reliability curve and average defect interval time (MTBF) of the DC protection system are obtained. Combined with the actual situation of the converter station, the DC protection system of the converter station is evaluated, which provides an important guiding basis for the subsequent maintenance, system transformation, and replacement of the converter station.
Single-pixel three-dimensional imaging for space-continuous targets based on compressive sensing
Authors: Wang Jing , An Yulong , Zhang Yanmei
Published: September 2020

In this paper, three-dimensional imaging method for space-continuous targets based on compressive sensing is investigated to get high precision imaging especially under low signal-to-noise ratio environments. Spatial correlation characteristic is adopted to enhance the anti-noise performance of imaging and the pulse echo attenuation characteristic is evaluated to settle the overlapping echo problem of space-continuous targets. Numerical simulations are performed to indicate the availability of our method and the experiment results demonstrate the applicability in 3D imaging, which is therefore fundamental to the complicated targets detecting and imaging with higher precision in the prospective practical applications.
Research on harmonic cooperative suppression strategy of hybrid parallel DC transmission system
Authors: Yan Han , Liu Ke , Wang Xuan , Che Keshan , Ding Yujie , Yang Wenli
Published: September 2020

Hybrid parallel DC transmission system has both flexible control characteristics of MMC-HVDC and large capacity transmission capacity of LCC-HVDC, which has good economy and practicability. However, the connection of hybrid parallel DC transmission system will bring a series of harmonic problems, so harmonic suppression measures must be taken. This paper firstly introduces the generation mechanism and basic characteristics of LCC-HVDC characteristic and non-characteristic harmonics. Then the causes of MMC-HVDC circulation are analysed. Finally, based on the parallel connection of LCC-HVDC and MMC-HVDC in the same AC bus, a harmonic co-suppression strategy of hybrid parallel DC transmission system is proposed and the simulation verification is carried out. The results show that the strategy can use MMC-HVDC to assist in absorbing the harmonics generated by LCC-HVDC.