bluuebunny/crossref_metadata_2025 huggingface dataset:
Human sapovirus propagation in human cell lines supplemented with bile acids
Authors: Takagi Hirotaka , Oka Tomoichiro , Shimoike Takashi , Saito Hiroyuki , Kobayashi Takayuki , Takahashi Tomoko , Tatsumi Chika , Kataoka Michiyo , Wang Qiuhong , Saif Linda J. , Noda Mamoru
Published: December 2020

Significance

Human sapoviruses (HuSaV) are an important cause of diarrhea and foodborne infections worldwide. Despite the discovery of HuSaVs over 40 y ago, no in vitro cell culture system has been established, limiting research on this important pathogen. In this study, we report successful propagation of HuSaV in a human duodenum cell line in the presence of bile acids. Bile acids are biological components in the intestinal tract, and they recapitulate key physiologic factors present in the viral infection site in the intestine. This inexpensive, reproducible and scalable in vitro cell culture system provides a fundamental scientific tool for HuSaV research and development of infection control strategies in the future.
Targeting presynaptic H3 heteroreceptor in nucleus accumbens to improve anxiety and obsessive-compulsive-like behaviors
Authors: Zhang Xiao-Yang , Peng Shi-Yu , Shen Li-Ping , Zhuang Qian-Xing , Li Bin , Xie Shu-Tao , Li Qian-Xiao , Shi Ming-Run , Ma Tian-Yu , Zhang Qipeng , Wang Jian-Jun , Zhu Jing-Ning
Published: December 2020

Significance

Anxiety disorders and obsessive-compulsive disorder (OCD) are highly prevalent and debilitating psychiatric disorders commonly co-occurring in our stressful modern life. Yet the common effective therapeutic target is still unknown. Here we report that activation of the histaminergic afferent system, particularly the histamine H3 receptor, in the nucleus accumbens (NAc) core, a vital node in the limbic loop, inhibits glutamatergic synaptic transmission in the circuit from the prelimbic prefrontal cortex (PrL) to NAc and improves both anxiety- and obsessive-compulsive-like behaviors induced by restraint stress. Our results define a common glutamatergic PrL–NAc circuit involved in both anxiety- and obsessive-compulsive-like behaviors modulated by the H3 presynaptic heteroreceptor and pave a path for developing potential strategies for clinical treatment of anxiety and OCD.
Time-dependent discrimination advantages for harmonic sounds suggest efficient coding for memory
Authors: McPherson Malinda J. , McDermott Josh H.
Published: December 2020

Significance

Sensory systems transduce information at high bandwidths but have limited memory resources, necessitating compressed storage formats. We probed auditory memory representations by measuring discrimination with and without time delays between sounds. Participants judged which of two sounds was higher. Discrimination across delays was better for harmonic sounds (containing integer multiples of a fundamental frequency, like many natural sounds) than for inharmonic sounds (with random frequencies), despite being comparably accurate without delays. Listeners appear to transition between a high-fidelity but short-lasting representation of a sound’s spectrum, and a compact but enduring representation that summarizes harmonic spectra with their fundamental frequency. The results demonstrate a form of abstraction within audition whereby memory representations differ in format from representations used for on-line judgments.
Planning universal accessibility to public health care in sub-Saharan Africa
Authors: Falchetta Giacomo , Hammad Ahmed T. , Shayegh Soheil
Published: December 2020

Significance

Achieving universal health care access is a key development priority and a target of Sustainable Development Goal number 3. The COVID-19 pandemic has only reinforced this urge. A rapid expansion of public, affordable health care infrastructure is particularly crucial in sub-Saharan Africa (SSA): communicable diseases are the first cause of death, infant mortality rates are above 5%, and lengthy journeys to health care facilities undermine the accessibility to basic health care for millions. This paper provides a planning-oriented, inequality-focused analysis of health care accessibility in SSA based on a state-of-the-art georeferenced database of public health care facilities. We devise a spatial optimization framework to identify the optimal location and required bed capacity of public health care facilities in the region.
The NLRP3 inflammasome inhibitor OLT1177 rescues cognitive impairment in a mouse model of Alzheimer’s disease
Authors: Lonnemann Niklas , Hosseini Shirin , Marchetti Carlo , Skouras Damaris B. , Stefanoni Davide , D’Alessandro Angelo , Dinarello Charles A. , Korte Martin
Published: December 2020

Significance

IL-1β is an immunomodulatory cytokine that is overexpressed in the brains of patients with Alzheimer’s disease (AD). The NLRP3 inflammasome is an intracellular complex that activates caspase-1, which processes the IL-1β and IL-18 precursors into active molecules. In this study, we used an APP/PS1 mouse model for AD, which confirms significant cognitive losses that are recovered in NLRP3-deficient mice, to evaluate the therapeutic potential of an orally bioavailable and safe NLRP3 inhibitor, OLT1177. OLT1177 ameliorated the phenotype in APP/PS1 mice, as evidenced by rescued spatial learning and memory in the Morris water maze test. Microglia were less activated, cortical plaques reduced, and plasma AD metabolic markers were normalized. OLT1177 is a potential therapeutic option for AD.
The potential harms of the Tor anonymity network cluster disproportionately in free countries
Authors: Jardine Eric , Lindner Andrew M. , Owenson Gareth
Published: December 2020

Significance

Measuring the proportion of Tor anonymity network users who employ the system for malicious purposes is important as this technology can facilitate child abuse, the sale of illicit drugs, and the distribution of malware. We show that only a small fraction of users globally (∼6.7%) likely use Tor for malicious purposes on an average day. However, this proportion clusters unevenly across countries, with more potentially malicious Tor users in “free” countries (∼7.8%) than in “not free” regimes (∼4.8%). These results suggest that the countries which host most of the infrastructure of the network and house the Tor Project plausibly experience a disproportional amount of harm from the Tor anonymity network.
TAT-RasGAP317-326kills cells by targeting inner-leaflet–enriched phospholipids
Authors: Serulla Marc , Ichim Gabriel , Stojceski Filip , Grasso Gianvito , Afonin Sergii , Heulot Mathieu , Schober Tim , Roth Robyn , Godefroy Cédric , Milhiet Pierre-Emmanuel , Das Kushal , García-Sáez Ana J. , Danani Andrea , Widmann Christian
Published: December 2020

Significance

TAT-RasGAP317–326can lyse cancer cells in a manner distinct from known programmed cell death pathways through its ability to target specific plasma membrane lipids. The killing properties of this peptide may therefore be difficult for cancer cells to alleviate through resistance-building alterations within known regulated cell death pathways. TAT-RasGAP317–326and compounds with similar anticancer activities can potentially complement existing anticancer therapies based on the use of genotoxins or radiation that induce apoptosis.
Control of
Drosophila
wing size by morphogen range and hormonal gating
Authors: Parker Joseph , Struhl Gary
Published: December 2020

Significance

During normal development, animals and their constituent body parts stop growing when they reach the right size. However, the mechanisms that limit growth as a function of size are largely unknown. Growth of the
Drosophila
wing, a classic paradigm, is governed by two morphogens, Decapentaplegic (Dpp, a BMP) and Wingless (Wg, a Wnt). We identify two constraints that cause the wing to cease growing when it achieves target size at the end of larval life: 1) an intrinsic limit on the spread of morphogen and 2) the capacity of the steroid hormone ecdysone to gate the ability of wing cells to grow in response to morphogen.
“A cool kid”
Authors: Bao Hongwei
Published: December 2020

This article traces the historical moment when queer theory first arrived in mainland China in the early 2000s by comparing and contrasting two translated texts in Chinese: Wang Fengzhen’s bookGuaiyi Lilun[Peculiar Theory] and Li Yinhe’s bookKu’er Lilun[A Cool Kid Theory]. Juxtaposing the two translators’ positioning and marketing strategies, along with their use of paratexts such as book cover design and translator’s prefaces, this article aims to explain whyKu’er Lilunended up being a more popular and widely circulated text thanGuaiyi Lilun. It also pinpoints the cultural specificities of queer theory’s reception in the postsocialist Chinese context at the beginning of the new millennium. This article hopes to provide critical insights into the politics of translating academic theories transnationally, with a focus on paratextual, extratextual, and contextual factors which work in tandem to shape the reception of these theories in a non-Western context.
Large-dynamic-range athermal lithium niobite on insulator/ TiO2 nanobeam electric field sensor
Authors: Ma Xinyu , Zhuang Chijie , Zeng Rong , Zhou Weidong
Published: December 2020

An integrated optical electric field (E-field) sensor based on a one-dimensional photonic crystal nanobeam cavity on a lithium niobite on insulator (LNOI) platform is reported here. It has a large dynamic range and extreme sensitivity. The dielectric resonant mode has a quality factor
Q
≳ 105. The waveguide-coupled structure, only 25 μm long, is beneficial for future on-chip integration. The use of TiO2 compensates for the thermo-optical effect of lithium niobite (LN), while the high dielectric constant of TiO2 influences the E-field distribution. A tri-layer TiO2/LNOI/TiO2 nanobeam structure is proposed to improve electro-optical modulation efficiency in LN. Detailed analysis of noise sources shows the theoretical minimum detectable E-field to be 0.15 V m−1 with a dynamic range of 83 dB. The temperature-induced resonant wavelength variation is within 3 pm °C−1 in the range of −40 °C to 40 °C.
Thermal conductivity of h-BN monolayers using machine learning interatomic potential
Authors: Zhang Yixuan , Shen Chen , Long Teng , Zhang Hongbin
Published: December 2020

Thermal management materials are of critical importance for engineering miniaturized electronic devices, where theoretical design of such materials demands the evaluation of thermal conductivities which are numerically expensive. In this work, we applied the recently developed machine learning interatomic potential (MLIP) to evaluate the thermal conductivity of hexagonal boron nitride monolayers. The MLIP is obtained using the Gaussian approximation potential method, and the resulting lattice dynamical properties and thermal conductivity are compared with those obtained from explicit frozen phonon calculations. It is observed that accurate thermal conductivity can be obtained based on MLIP constructed with about 30% representative configurations, and the high-order force constants provide a more reliable benchmark on the quality of MLIP than the harmonic approximation.
Minimal length effects on motion of a particle in Rindler space *
Authors: Guo Xiaobo , Liang Kangkai , Mu Benrong , Wang Peng , Yang Mingtao
Published: December 2020

Various quantum theories of gravity predict the existence of a minimal measurable length. In this paper, we study effects of the minimal length on the motion of a particle in the Rindler space under a harmonic potential. This toy model captures key features of particle dynamics near a black hole horizon and allows us to make three observations. First, we find that chaotic behavior becomes stronger with increases in minimal length effects, leading predominantly to growth in the maximum Lyapunov characteristic exponents, while the KAM curves on Poincaré surfaces of a section tend to disintegrate into chaotic layers. Second, in the presence of the minimal length effects, it can take a finite amount of Rindler time for a particle to cross the Rindler horizon, which implies a shorter scrambling time of black holes. Finally, the model shows that some Lyapunov characteristic exponents can be greater than the surface gravity of the horizon, violating the recently conjectured universal upper bound. In short, our results reveal that quantum gravity effects may make black holes prone to more chaos and faster scrambling.
Production Performance Analysis of Su-6 Well Block in Sulige Gas Field, Ordos Basin, China
Authors: Sun Lin , Li Xianwen , Chen Baochun , Gu Yonghong , Wang Wenxiong , Zhao Jinsheng
Published: December 2020

As a tight sandstone gas reservoir of Su-6 well block in Sulige gas field, part of the gas wells have a poorer production performance with a faster decline rate of formation pressure and production, which is inconsistent with static reservoir parameters of gas well. In order to improve the productivity of gas well, on the base of static and dynamic classification of 232 gas wells, the reasons of inconformity between production performance and static reservoir parameters are analyzed from the four aspects of sand body connectivity, reservoir heterogeneity, gas saturation and fluid accumulation in wellbore. The results show that the main reasons causing the inconformity are the strong heterogeneity and poor sand body connectivity, and the secondary reasons are fluid accumulation in wellbore and low gas saturation. The results of this paper is of great significance to improve the productivity of gas wells and guide the development of ultra-low permeability gas reservoir.
Situation Analysis on the Price Formation Mechanism of New Energy in China
Authors: Mi Ning , Liu Dunnan , Qiao Ning , Wang Liyang , Li Qiang , Zhang Chao , Xu Xiaofeng , Yin Guolong
Published: December 2020

With the rapid development of China’s economy, the energy shortage is becoming more and more serious. In order to realize the sustainable development of society, Chinese government has strengthened its support for the development of new energy industry. At present, the total installed capacity of new energy in China has reached 37.2%. Compared with the initial period, the scale of new energy industry has been greatly increased. However, the problem of pricing mechanism of new energy benchmarking in China is increasingly prominent, which not only increases the gap of financial subsidies, but also fails to realize the reasonable optimal allocation of resources. For this purpose, according to the current domestic electricity market environment, this article proposes a new energy price formation mechanism which is more conformed to China’s national conditions. Firstly, the article summarizes the existing international new energy pricing mechanisms and analyses the countries in which they are applied. Secondly, through the analysis of the problems and challenges of new energy price in China, the formation mechanism of new energy price in this environment is proposed according to the current situation and future development trend of power market construction in China. Finally, the article summarizes the whole text and proposes relevant policy recommendations as a useful reference for the government to promote the construction of electricity market.
Well loss Risk Real-time Monitoring and Simulation Analysis of Key Parameters
Authors: Ma Yongqian , Shao Ru , Dong Guanghua , Liu Xiaolan
Published: December 2020

The downhole engineering parameters measurement system(EPMS) can show the actual state in wellhole more intuitively, and significantly improve the accuracy of drilling construction decision. However, there was a big gap between domestic and foreign countries in the comprehensive management, analysis and processing of underground and surface drilling engineering parameters. For the well loss risk, the characteristic parameters were internal and external pressures, and the threshold limit values of well loss risk levels was selected, so the assessment system was established. Then through real-time processing and analysis of underground and surface engineering parameters, the characteristic parameters of the well loss risk was calculated real-time, according to the comparison of the calculated value and the measured value, and the assessment system, the wellhore risk level was monitored real-time. Beside the well loss depth could be calculated by these measured parameters, which was important for the well loss treatment. This technology was used in G1 well in GX blocks of Shengli oilfield, in which the well loss occurd frequently. The application result shows that well loss can be monitored at an early stage, reducing the cost of materials and processing the complex time.
Study of a Novel High-Density Module with Triangled Light Redirecting Ribbons
Authors: Huang Guoping , Zhuang Hao , Jiang Yashuai , Sun Guan , Bai Xueliang , Li Jingnan
Published: December 2020

Light redirecting ribbons (LRR) have recently been applied in high-density crystalline silicon modules in PV industry. The adoption of this LRR may bring additional reliability risk, which may probably lead to higher power loss after aging. Therefore, damp heat (DH), thermal cycle (TC), UV irradiation and humidity freezing (HF) test were employed in this work to investigate the reliability of LRR-based high-density crystalline silicon modules. The obtained results show that this novel high-density modules with specially designed triangle ribbons have outstanding reliability both in damp heat and dry heat environment as well as under UV irradiation.
Off-design Characteristics for Expansion Power Generation Process of Liquid Air Energy Storage System
Authors: Xu Guizhi , Deng Zhanfeng , Cui Shuangshuang , Shi Xingping , Lu Chang , Liang Lixiao , He Qing
Published: December 2020

In order to study the off-design conditions of energy storage system due to the grid load requirements and the fluctuation of external environmental factors in the process of grid-connected operation and the off-design performance of energy storage system, the dynamic model of expansion power generation of 500kW liquid air energy storage (LAES) system is established. Considering the change characteristics of the adiabatic efficiency and pressure ratio of the expander with flow rate, the dynamic changes of rotor speed, electric power, and valve opening size of LAES system under complex conditions of increasing/decreasing load are simulated. The results show that the stability time of electric power is shorter when the variable load is lower when the load change rate of the energy storage system is kept constant under the condition of increasing/decreasing load. On the contrary, the stability time of electric power is longer when the variable load is higher. The stability time of electric power is 12s when the energy storage system changes from 100% rated condition to 90% working condition. The stability time of electric power is 34s when the energy storage system changes from 100% rated working condition to 60% working condition. Under the condition of variable load, the fluctuation of rotor speed is very small and remains unchanged.
Problem and Countermeasure Analysis of IGCC Combustion Gas Turbine Fueled with Low Heating Value Syngas
Authors: Liu Hongtao , Xue Li , Wang Xueqing , Zhang Huanxiang
Published: December 2020

IGCC technology is recognized as one of the cleanest and most efficient power generation technologies. Inferior fuel is gasified into clean syngas by IGCC gasification reaction. Syngas is then sent to combustion gas turbine and combusted to generate power. Problem and countermeasure of IGCC combustion gas turbine fueled with low heating value syngas is analyzed in this paper. Main fuel components and combustion characteristics of syngas are significantly different with that of conventional natural gas. Diffusion combustion mode is adopted to match syngas combustion characteristics. The gas turbine will trip due to unstable combustion if direct burning syngas at low load case. Alternative fuels should be used at low gas turbine load case. There is an appropriate load window for fuel switching. Fuel switching at 50% load within 10 minutes is selected in this paper.
Study on Guided Wave Characteristics of Waveguide Rod
Authors: Meng Xiangjun , Li Wenfeng , Sun Peng , Zhang Xiaofei , Wu Jialing , He Qing
Published: December 2020

Waveguide rod is currently used as an auxiliary tool in ultrasonic testing. Because the waveguide rod can isolate high-temperature workpiece from ultrasonic sensor, it is often used in monitoring of high-temperature equipment. However, there are dispersion and attenuation when ultrasonic guided wave propagates in waveguide rod, which is not conducive to the monitoring of equipment. In order to improve the monitoring accuracy, the effects of diameters and lengths on the guided wave characteristics of the waveguide rod were analyzed through numerical calculation and experimental research. The results show that the larger the diameter of the waveguide rod, the smaller the attenuation of the ultrasonic guided wave and the weaker the dispersion; the increase in the length of the waveguide rod has no effect on the dispersion of the guided wave, but it will increase the attenuation.
Design of Power and Energy System for a Small Garbage Cleaning Ship
Authors: Zhang Wei , Jiang Dezhi , Li Pinfang
Published: December 2020

Port garbage and dirty oil will cause pollution to the marine environment, and the sea area of port is narrow and not easy to clean, which limits the use of conventional cleaning ships. There is a need for an environmentally friendly and flexible small garbage cleaning ship. This study introduces the composition and principle of the ship propulsion system, analyzes and calculates the characteristics of the motor and the power of the ship shaft, determines the type of the motor and the composition of the energy system, and further analyzes and calculates the solar power generation system. The results show that the mode of using lithium battery as main energy and solar energy as auxiliary energy can meet the power needs of the small cleaning ship and meet the relevant environmental protection requirements.
Double Rotary Valve Engine Design
Authors: Deng Baoqing , Liu Zhuoya , Gao Zengfa , Li Shihang , Deng Mengqi
Published: December 2020

This paper proposes a new type of dual-rotation valve engine, which uses the intake rotary valve and the exhaust rotary valve to control the intake and exhaust of the engine, replacing the intake and exhaust valves and camshafts of the conventional engine. The basic mechanism and working principle of the machine are discussed. In this paper, the combustion chamber structure and lubrication method of the machine are also designed. The compression ratio of the machine is calculated, the gas distribution phase is designed, and the ventilation passing ability is analyzed. It is concluded that the machine has the advantages of simple structure, few parts and strong ventilation capacity, that is, it is suitable for port injection and can also carry out in-cylinder injection.
Study on the Mechanism of High-Silicon Manganese Fume Dust Precipitation under Pressure by Acid Pickling
Authors: Li Kaifeng , Xie Hongyan , Jin Huixin , Zhang Qiang , Zhang Yaqing , Li Xiaohui , Bao Chongjun
Published: December 2020

Via the thermodynamic analysis of high silicon manganese soot precipitation process. Potential-oxidation state-ΔG diagram, E-pH diagram, micro-region morphology of manganese soot and X-ray energy spectrum analysis, we can know: under high temperature leaching conditions, the leaching system needs to maintain a relatively high initial acid concentration in order to achieve leaching of Mn2+ and increase the pressure leaching rate.
Numerical Simulation of the Effect of Combustion Process on Flue Gas Thermal Deviation in 660MW Boiler
Authors: Yang Xianbiao , Gao Yuan , Wang Shutao , Shi Renqiang , Liang Shaohua , Sun Rongyue
Published: December 2020

In order to analyze the effect of the air volume on the combustion side and the non-uniformity of pulverized coal on the temperature distribution of the boiler outlet flue gas, and then analyze the thermal deviation characteristics of the steam heating surface, the following five different working conditions are calculated and analyzed in a 660MW boiler. Results show that the deviation of pulverized coal content of each burner and the deviation of primary air volume are the important factors that cause the temperature deviation of flue gas outlet in the furnace. Therefore, it is an important way to improve the temperature distribution and reduce the thermal deviation of flue gas outlet by improving the uniform combustion and air distribution of the burner in the furnace.
Research and Development of Fire Alarm Detection Device for Lithium Ion Battery Based on Strain Measurement
Authors: Xiaobai Li , Xiaopeng Liu , Yingcong Zhang
Published: December 2020

In order to realize the fire alarm of lithium ion battery, a fire alarm detection device is developed based on the principle of strain measurement. This paper makes a study of the detection principle and application circuit. Firstly, according to characteristic rule of thermal runaway process of lithium ion battery, the correlation between battery deformation, temperature and released gas is analyzed and a battery fire warning method based on strain measurement is proposed. Then, the strain measuring circuit is designed and circuit working principle is analyzed. In the end, the application effect of the battery fire warning method based on strain measurement is verified through thermal runaway experiment of lithium ion battery. The experimental results show that the method based on strain measurement can identify fire risks at the early stage when the lithium ion battery thermal is out of control, preventing fire from spreading. Basically it can meet the needs of lithium-ion battery fire warning.
Effect of the surfactants on hydrate formation during methane storage process
Authors: Zhang Panfeng , Diao Yuqian , Dong Zhao , Pei Shufeng , Wang Qiaobo , Ren Shaoran , Zhang Liang
Published: December 2020

Enhanced hydrate formation rate by adding surfactant for achieving hydrate-based methane storage and transportation has drawn much attention in recent years. In this study, the effect of cocamidopropyl dimethylamine (CPDA), Sodium dodecyl sulfate (SDS), dodecyl trimethyl ammonium bromide (DTAB), and hexadecyl trimethyl ammonium bromide (HTAB) on induction time, the formation rate, water conversion ratio, and dissociation rate of methane hydrate have been investigated. And all the results have been compared with the water system without any additives. After adding surfactant into the aqueous solution, the hydrate formation is promoted, which lead to higher the hydrate formation rate and more water converted to be hydrate. 69.96wt% water was converted to be hydrate and its formation rate is 31.58mmol/min in 1.0wt%CPDA aqueous solution, in water without any additives system, it is 29.44wt%, 11.45mmol/min, respectively. Besides, the highest dissociation rate is also found in CPDA aqueous solution system, it is 42.2mmol/min and is 2.16 times than that of the pure water system.
Study on variational assimilation in chemical hazard leakage accidents
Authors: Jiang Jinli , Han Chaoshuai , Zhu Xuezheng , Gu Jin
Published: December 2020

In this paper, the problem is studied and analyzed by introducing variational assimilation method and combining with the gaussian plume model.Through the analysis and study of background error covariance, observation error covariance and diffusion parameters, the variational assimilation scheme of chemical hazards was designed and the mathematical modeling was carried out.Then, through Matlab platform programming, numerical experiments are carried out on the established model and an example analysis is made. The results show that the concentration prediction field after assimilation can effectively reduce the prediction error and achieve convergence.
Research on Application of Image Enhancement Technology in Automatic Recognition of Rock Thin Section
Authors: Xu Yuxuan , Dai Zongyang , Luo Yixin
Published: December 2020

Artificial intelligence technology has rapidly emerged in various new industries due to its high efficiency and has been successfully used in many fields. However, it has been slow to start in the field of petroleum exploration, under the background of the need for more efficient exploration and development in the petroleum field. In this paper we used the ResNet-18 convolutional neural network to make an attempt to automatically identify rock thin section, and finds that this method can efficiently identify rock thin section and has a higher accuracy rate. In addition, we adopted appropriate image enhancement technology, which can significantly improve the recognition accuracy of the model. It proves that related machine learning technology has broad application prospects in the fields of petroleum exploration and petroleum geology.
Study on the Law of the Influence on Slag Blocking in Combustors Produced by Coal Blending Combustion Strategy of Slag-tap Boiler
Authors: Xiang Ma , Hao Zhou
Published: December 2020

Slag blocking and slagging of combustors are influenced by the coal blending combustion strategy of slag-tap boiler. this paper studies these influence factors, analyzes the problems of slag blocking and slagging of combustors from the perspective of fuel, and examines the calorific value, ash content, ash melting point, ash melting characteristics of coal quality and slag captured rate of boiler. Based on the above researches, the writer summarizes the effects on slag blocking and slagging in the combustors produced by different coal combustion of slag-tap boiler, and forms coal blending combustion strategy suitable for the slag-tap boiler.
Analysis on factors that influence concentration of PM2.5 expelled in vehicle exhaust in underground parking lots of large shopping centers in Changchun
Authors: Bai Li , Fu Jia-Qian , Sun Yu-Tong
Published: December 2020

Our goal is to find out how the passenger number, vehicle type and vehicle displacement influence the PM2.5 concentration in underground parking lots of large shopping centers. To this end, we collected data of PM2.5 concentration in several underground parking lots in CBDs of Changchun. We have some findings from the conducted experiments. First, PM2.5 concentration rises as the the number of passengers carried in the vehicle increases. As for vehicle type and displacement, high-displacement sedans and moderate-displacement SUVs contribute most to PM2.5 concentration inside the parking lots, among which vehicles of older age cause even greater pollution, with PM2.5 concentration averaging 208 μg/m³and 241μg/m³respectively. And high-displacement MPVs have greater influence on PM2.5 concentration than low-displacement ones.
Pyrogenic transformation of old pine forests in the Middle Volga Integrated Biosphere Reserve and its effect on the nesting birds
Authors: Bykov E V , Golovatyuk S A
Published: December 2020

The effects of the pyrogenic transformation of old pine forests of the Middle Volga Integrated Biosphere Reserve on the nesting birds were studied, based on the original surveys performed in 2006-2009. The changes of the breeding ornithological fauna’s parameters were traced during the restoration of the lower tiers of vegetation after local lower fires. The response of particular species and guilds of nesting birds to the changes in nesting conditions due to a single bottom fire was determined, as well as the changes in the total number of nesting birds and in the number of particular guilds of nesting birds during the vegetation recovery after the fire. The bird species vulnerable to the changes in nesting conditions were identified. The relationship between post-pyrogenic vegetation restoration processes in old pine forests and the species composition and ecological preferences of birds nesting was shown.
Taxonomic composition of the bacteriobenthos of the littoral and pelagic zones of the Lake Kandry-Kul in June and September 2010 (Natural Park “Kandry-Kul”, Republic of Bashkortostan, Russia)
Authors: Sherysheva N G , Rakitina T A , Povetkina L P
Published: December 2020

The taxonomic composition of the bacteriobenthos of the littoral and pelagic zones of the Lake Kandry-Kul’ was analyzed by gas chromatography-mass spectrometry (microbial markers). The studied communities comprise 39 taxa of the Bacteria domain. Two dominant taxa were a characteristic of bacteriobenthos in the littoral zone in June, one dominant taxon, in September. The taxonomic structure of bacteriobenthos of the pelagic zone was characterized by two dominant taxa both in June and September. There were common dominants in the littoral and pelagic biotopes, namely, representatives of the genera Butyrivibrio, Spirochaeta, and of the group of iron-reducing bacteria (FeRB). The species Clostridium difficile, Geothrix fermentans, and the genus Thiobacillus were specific to the littoral bacteriobenthos community. The bacterial community of the pelagic zone was characterized by a change of dominant taxa in autumn. The increase of bacteriobenthos biomass and its particular taxa was significantly affected by the water temperature, redox potential, and the content of humic substances.
Nuisance algae Gonyostomum semen (Raphidophyta) in water bodies of protected natural areas in Middle Volga region (Russia)
Authors: Umanskaya M V , Tarasova N G , Bykova S V , Yu Gorbunov M
Published: December 2020

The distribution if nuisance raphidophyte Gonyostomum semen in water bodies of protected natural areas of the Middle Volga region is analyzed. The abundance of the species was determined quantitatively in eight lakes using the method of fixation with mercuric chloride. In four more lakes, it was found by qualitative inspection of live samples. It develops mainly in lakes with high water color, reaching the cell number of 7.5 106 cells L1, but also occurs in clear-water lakes in minor abundance (10-1600 cells L−1). It has been demonstrated that some ciliate species e.g. Frontonia leucas can consume G semen cells and therefore partially control its abundance. Taking into account the presented data, this species was recorded in the plankton of lakes in all regions of the forest part of the Middle Volga basin. Thus, these results significantly expand the geography of the planktonic habitats of G semen in the whole Volga region.
Virtual Synchronous Control for Fuel Cell Power Generation System
Authors: Ge Yi , Zhao Yangyang , Li Hu , Tan Jian , Chen Hui
Published: December 2020

In this paper, the concept of FC-VSG is proposed to operate a fuel cell power generation (FC) as a virtual synchronous generator (VSG). In order to provide the sufficient frequency and voltage support for the grid, the grid inverter in such a FC-VSG system is controlled to generate an appropriate voltage similar to the conventional synchronous generator. As a result, the overall system behaves like a VSG, which is significantly different from simply controlling the FC as a current source. It is able to provide the hydrogen energy stored in the fuel tank as inertia to support the grid frequency and also to provide reactive power to support the grid voltage. Moreover, the system does not need a phase-locked loop (PLL), and the seamless transition between grid-connected mode and islanded mode can be easily achieved. Simulation results from a 1 MW fuel cell power generation connected to an AC grid is presented to demonstrate the feasibility and effectiveness of the strategy.
How Does Urban Park Affect People’s Health? An Empirical Study Based on Xiaoyaojin Park in Hefei
Authors: Wang Zhipeng , Xing Siyi , Zhang Bo , Liang Wanning , Zhu Yating
Published: December 2020

As one of the important forms of urban space, urban parks not only provide green space, but also support a variety of outdoor recreation activities. They play an important role in the life of urban residents’ sports, leisure and social interaction, and have great potential effect on promote people’s physical and mental health. This study used a questionnaire survey method, SF-12 health questionnaire was used to quantify the physical and mental health of park users. Satisfaction questionnaire was used to evaluate park users’ satisfaction with park characteristics. Multiple regression analysis was used to reveal the relationship between urban park and park users’ physical and mental health score. The results show that there is a positive correlation between the time of using the park, the satisfaction with the overall environment of the park and their scores of physical and mental health. Park users’ satisfaction with the activity facilities of the park is positively correlated with their physical health score, and their satisfaction with the plant landscape of the park is positively correlated with their mental health score. The conclusion shows that urban parks have a positive impact on people’s physical and mental health.
Prediction of the properties of photopolymer prototypes
Authors: Shumkov A A , Ablyaz T R , Muratov K R , Sidhu S S
Published: December 2020

The study of the mechanical properties of photopolymer material SI500. For the manufacture of experimental samples used the method of rapid prototyping stereolithography. The effect of process parameters on tensile and compression strength was studied. It was found that the mechanical strength of the samples is influenced by the layer thickness, exposure time, and additional processing in an ultraviolet chamber. The values of maximum tensile stresses, which are achieved when the layer is exposed for 30 seconds and additional processing, are determined. Changing the layer thickness does not significantly affect the values of maximum tensile stresses. The maximum is in the range from 53.4 MPa to 55.4 MPa. Values of maximum mechanical strength during compression of the samples is achieved with a flash of 10 seconds. The maximum compressive stresses range from 229 MPa to 230 MPa. Changing the layer thickness does not significantly affect the compressive strength.
Visualization models of technological heredity in mechanical engineering
Authors: Konoplin Alexander , Baurova Natalia , Abrakov Sergei
Published: December 2020

By the example of machine-building products the model of visualization of their quality indicators at different stages of life cycle is offered. It is shown that to visualize the influence of technological heredity on the quality indices of the product it is most demonstrative to use the graph theory and the Liebich metaphorical barrel. The proposed approach allows to use the principle of cybernetics, according to which the product, at each stage of its life cycle, is presented in the form of a set of separate elements connected with each other in a single information network. The joint use of the graph theory and the Liebich metaphorical barrel allows evaluating the studied indices and visually displaying them in the complex. The main advantage of this approach is the ability to illustrate which of the set of quality indicators of a particular product is most significant.
Heat model of a spindle support of a precesion metal cutting machine
Authors: Denisenko A F , Podkruglyak L Y
Published: December 2020

Based on the use of the electrothermal analogy in describing the heat transfer process, an engineering technique has been developed to determine the thermal state of the supports of spindle assemblies, which does not require “heavy” software packages based on the application of the finite element method. The design features of modern control rooms made it possible to reasonably present the thermal model in the form of a flat model. The principles of dividing the blocks of a flat model into enlarged elements are proposed, taking into account the features of the geometry of the calculated structure and heat sources. A technique has been developed for determining the thermal resistance of an element of a calculated thermal model taking into account boundary conditions. The use of enlarged elements of the thermal model makes it easy to assess the influence of technological features of processing and assembly of individual structural parts on its thermal state. The presented methodology for developing a thermal model can be used to estimate stationary thermal processes of any axisymmetric structures with insignificant temperature variations.
Thermal strengthening treatment of low-rigid lead screws
Authors: Bobrowski A V , Drachev O I , Turbin I V , Epishkin V E
Published: December 2020

The article deals with the design of equipment for thermal strengthening operations (hardening, tempering and normalization) of low-rigid long-length lead screws of high accuracy. The technology of thermal strengthening processing is given. In this paper, a new approach is proposed to the processing of lead screws and their treatment technology to obtain high geometric accuracy. Relatively long and thin products are characterized by common deviations of shapes from the straightness of the axis and the uneven pitch of the helix. The technological process of their production should include bending operations and multiple tempering to stabilize residual stresses. This ensures the straightness of the part and the stability of the thread pitch. As an effective method and promising direction, a thermal strengthening processing is proposed. Recommendations are given on technical methods of axial deformation and determination of the optimal modes of thermal strengthening. The principle of operation of the installation and algorithms of the technological process are described.
Improving lathe dynamics by workpiece - support subsystem control
Authors: Bobrovsky A V , Drachev O I , Epishkin V E
Published: December 2020

The article discusses the design of the lathe, the peculiarity of which is the equipment of it with three automatic control systems (ACS) of the workpiece-support subsystem. The first ACS ensures the stability of the workpiece axis during machining by controlling the self-centering supports (SCS). The second ACS controls the dynamics of the spindle assembly. The third ACS controls the axial clamping of the rear center, which enables machining low rigid small, long shaft-type workpieces for turning, grinding and milling spline slots. The use of ACS increases the accuracy, quality of machining and vibration resistance of the Lathe - Device - Tool - Workpiece (LDTW) system, which is achieved in all operations through automatic control of tool positions and the workpiece. In addition, the residual stress on the machined surfaces is reduced by introducing high-frequency vibrations into the cutting area at all operations.
To the definition of stress-strain state of springs during recovering when hardened
Authors: Zemlyanushnov N A , Zemlyanushnova N Y
Published: December 2020

The results of experimental work on the recovering of springs are presented. A methodology is proposed for theoretical determination of the parameters of springs during recovering using low-temperature thermomechanical treatment (tension with heating), shot peening and contact hardening.
Fuzzy control under uncertainty in machine building
Authors: Ablyazov V , Drachev O , Tisenko V
Published: December 2020

This report addresses the aspects of decision-making problems during asset management in cases when there is an uncertainty of the situation that can be caused by complexity of an asset or insufficient information about it. In last decades, the fuzzy logic proposed by Lotfi Zadeh has been successfully used in such cases. This report also considers positive and negative aspects of this form of logic and proposes using fuzzy converse logic (antonyms-related), which is free from weaknesses of fuzzy-related concepts proposed by Zadeh. We outline the basic axioms of converse logic and its application for decision-making problems during asset management under uncertainty.
Study of possibility to process the edges of the parts on the robot
Authors: Podashev D
Published: December 2020

The necessity to replace manual labour for mechanized and automatic is very actual for mechanical engineering. The possibility to implement the robot complex (RC) when processing the edges of the parts is studied in the report. Polymer-abrasive radial and end brushes were used as tools. Usage of processing of edges on RC by elastic polymer-abrasive brushes with different combination of surfaces on parts proved that such an operation can be implemented successfully with meeting all requirements on quality of processed edges.
Dependence of abrasive tool wear-resistance on abrasive grain microstrength
Authors: Bagaiskov Yu
Published: December 2020

Microstrength determined applying the microindentation method is an essential indicator of micromechanical properties of abrasive tools’ grains. Assessment is carried out according to the damage area dimensions and the imprint depth. The test results of various materials, including abrasive materials, in a friction machine revealed that relative wear-resistance of those materials depends on microstrength. The higher microstrength is, the lower wear-resistance of materials is. Such dependence was revealed in the course of studying the process of microcutting by single abrasive grains, as well as evaluating specific capacity of abrasive tools in operation. Thus, the microstrength parameter can be used to forecast operational efficiency of materials and tools.
Simulation of upsetting process using kinematic schemes of metal flow
Authors: Solomonov K N , Tishchuk L I , Lezhnev S N , Listrov E A
Published: December 2020

The problems of simulation the on the basis of kinematic schemes of metal flow, which is observed in the processes of forging and stamping workpieces with flat areas, are considered. Presented traditional kinematic schemes of metal flow: normal and radial. To solve these problems, a modernized program complex EQUI was developed, which is used for computer simulation of metal flow in the workpiece plane. It is shown that for any parameters of upsetting process is a real «intermediate» kinematic scheme of metal flow, which consists of areas of the flow normal to the contour and areas of radial flow. The results of a virtual experiment were obtained using the program complex DEFORM, which has proven well in solving plastic forming problems. For computer simulation of the spatial diagram of contact stresses and the dividing line of metal flow is selected known software COMPAS. The horizontal projection of the solid model allows you to get an image of the dividing line of metal flow. Comparison of results, obtained in the COMPAS and EQUI, shows good agreement.
Development the assembly sequence mathematical modeling method of precision axisymmetric products based on the graph incidence matrix
Authors: Volkov I A , Primak D D , Artykh R L , Bazhenov R I
Published: December 2020

The paper presents a method for problem solving of automated construction the assembly sequence of high-precision axially symmetric products. The purpose of this article is testing the admissibility of using a directed assembly graph, including adjacency and incidence matrices, for structuring and planning theoretical schematization of the assembly technological process. The considered method coincides with a possible mathematical implementation of the problem. The specificity of the structure modeling and the assembly process using mathematical methods has been evaluated. The graph creating technique representing the relationship between parts and the assembly process is considered. The solving the problem of assembly process automated construction is performed using algorithms and computational software based on the graphs constructing of in the matrices form. A comparison of the results achieved theoretically and computer aided in terms of designing the assembly process has been made. The achieved results make it possible in real time to adjust the productassembly sequencing, on the basis of this, it becomes possible to track parameters and control decision-making when planning assembly processes.