bluuebunny/crossref_metadata_2025 huggingface dataset:
Computation offloading in cognitive radio NOMA‐enabled multi‐access edge computing systems
Authors: Nguyen Chuyen T. , Pham Quoc‐Viet , Pham Huong‐Giang T. , Dao Nhu‐Ngoc , Hwang Won‐Joo
Published: October 2020

The explosive growth of end devices and mobile applications calls for novel schemes that can enable computation‐hungry applications at small end‐devices and meet the massive connectivity requirement. Cognitive radio (CR), non‐orthogonal multiple access (NOMA) and multi‐access edge computing (MEC) are envisioned as the key technologies in fifth‐generation and beyond. In this work, the authors introduce the concept of CR‐NOMA in MEC offloading, where a secondary user (SU) can utilise the spectrum allocated to a primary user (PU) to offload its computation task to the MEC server for remote execution. For the spectrum utilisation, an equation to specify the minimum transmit power that must be allocated to the PU is derived. The authors also develop an algorithm to determine the offloading decision (i.e. offloading or not) and the paired PU (i.e. subcarrier used for computation offloading) for SUs, using one‐to‐one matching game. Moreover, through numerical simulations, the authors demonstrate the superior performance of the proposed algorithm compared with several baseline schemes.
Dual‐ordered non‐orthogonal multiple access with decode and forward relaying
Authors: Misra Aradhana , Sarma Kandarpa Kumar
Published: October 2020

Cooperative non‐orthogonal multiple access (NOMA) system has demonstrated the ability to improve spectral efficiency, massive connectivity, and spectral efficiency. In this study, the authors propose a novel dual‐ordered NOMA in a decode and forward (DF) relaying network, where a dynamic channel ordering is considered at both source and relay nodes during the symbol transmission period. The proposed NOMA system uses instantaneous channel gain as the channel state information (CSI) measure for channel ordering of the NOMA users in contrast to the more popular statistical CSI measures. We have established the efficiency of the proposed method through investigation of three different performance metrics: outage probability, ergodic rate analysis, and fairness of the proposed scheme in a downlink NOMA network with DF relaying. The results obtained show superior performance of the double ordered NOMA as compared to the single‐ordered NOMA.
YOLOpeds: efficient real‐time single‐shot pedestrian detection for smart camera applications
Authors: Kyrkou Christos
Published: October 2020

Deep‐learning‐based pedestrian detectors can enhance the capabilities of smart camera systems in a wide spectrum of machine vision applications including video surveillance, autonomous driving, robots and drones, smart factory, and health monitoring. However, such complex paradigms do not scale easily and are not traditionally implemented in resource‐constrained smart cameras for on‐device processing which offers significant advantages in situations when real‐time monitoring and privacy are vital. This work addresses the challenge of achieving a good trade‐off between accuracy and speed for efficient deep‐learning‐based pedestrian detection in smart camera applications. The contributions of this work are the following: 1) a computationally efficient architecture based on separable convolutions that integrates dense connections across layers and multi‐scale feature fusion to improve representational capacity while decreasing the number of parameters and operations, 2) a more elaborate loss function for improved localization, 3) and an anchor‐less approach for detection. The proposed approach referred to as YOLOpeds is evaluated using the PETS2009 surveillance dataset on 320 × 320 images. A real‐system implementation is presented using the Jetson TX2 embedded platform. YOLOpeds provides real‐time sustained operation of over 30 frames per second with detection rates in the range of 86% outperforming existing deep learning models.
Split ratio optimisation of high‐speed permanent magnet synchronous motor with multi‐physics constraints
Authors: Qin Xue‐fei , Shen Jian‐xin
Published: October 2020

Split ratio is one of the most crucial parameters in a permanent magnet synchronous machine (PMSM), which has great impact on both machine torque or power, and efficiency. Extensive studies have been carried out on the split ratio optimisation. Compared with the regular‐speed machines, the high‐speed PMSM has more types of power loss playing dominant roles, and has deeper coupling of multi‐physics fields. Therefore, special concerns need be made. More comprehensive and accurate power loss estimation should be implemented; both of the critical mechanical stress constraint of the rotor and the critical thermal constraint, which in turn are associated with the machine electromagnetic performance, should be analysed and must be satisfied during optimal design. All these concerns will be presented in this study. Based on these, a procedure of the split ratio optimisation is proposed. It solely uses analytical equations which are derived in this study, hence it is simple and fast. A 250 kW, 25 krpm high‐speed PMSM is taken as a study case, and its optimisation results using the proposed procedure are validated with finite‐element analysis. Moreover, influence of the split ratio on various machine performances is discussed.
Two‐stage game framework for energy management in islanded multi‐microgrid system
Authors: Lei Chen , Yugang Niu
Published: October 2020

A multi‐microgrid system is composed of multiple low‐voltage microgrids and the distributed energy connected to adjacent feeders. Considering the uncertainty factors, this study presents a two‐stage game framework to achieve energy management in the daily operation of islanded multi‐microgrids. In the upper stage, the power surplus and power shortage conditions of microgrids are analysed and the corresponding profit models are established. Then, during this cooperative game, each microgrid maximises its own profits through transactions and achieves a win–win situation by changing the number of coalition members. In the lower stage, the uncertainty models of both the photovoltaic power generation and the controllable load are constructed to achieve the maximum match between the power generation and the load curve. Finally, it is shown via a practical example that the proposed method can effectively promote the total profit of the islanded multi‐microgrid system.
Recognition of cursive video text using a deep learning framework
Authors: Mirza Ali , Siddiqi Imran
Published: October 2020

This study focuses on cursive text recognition appearing in videos, using a complete framework of deep neural networks. While mature video optical character recognition systems (V‐OCRs) are available for text in non‐cursive scripts, recognition of cursive scripts is marked by many challenges. These include complex and overlapping ligatures, context‐dependent shape variations and presence of a large number of dots and diacritics. The authors present an analytical technique for recognition of cursive caption text that relies on a combination of convolutional and recurrent neural networks trained in an end‐to‐end framework. Text lines extracted from video frames are preprocessed to segment the background and are fed to a convolutional neural network for feature extraction. The extracted feature sequences are fed to different variants of bi‐directional recurrent neural networks along with the ground truth transcription to learn sequence‐to‐sequence mapping. Finally, a connectionist temporal classification layer is employed to produce the final transcription. Experiments on a data set of more than 40,000 text lines from 11,192 video frames of various News channel videos reported an overall character recognition rate of 97.63%. The proposed work employs Urdu text as a case study but the findings can be generalised to other cursive scripts as well.
Image compression using adaptive multiresolution image decomposition algorithm
Authors: Alkishriwo Osama A.S.
Published: October 2020

With the growth of modern digital technologies, demand for transmission multimedia and digital images, which require more storage space and transmission bandwidth, has been increased rapidly. Hence, developing new image compression techniques for reducing data size without degrading the quality of the image, has gained a lot of interest recently. In this study, an adaptive multiresolution image decomposition (AMID) algorithm is proposed and its application for image compression is explored. The developed algorithm is capable of decomposing an image along the vertical, horizontal, and diagonal directions using the pyramidal multiresolution scheme. Compared to the wavelet transform, the AMID can be used for decimation with the guarantees of perfect signal reconstruction. Furthermore, the application of the AMID for image compression is explored and its performance is compared with the state‐of‐the‐art image compression techniques. The performance of compression method is evaluated using peak signal‐to‐noise ratio and compression ratio. Experimental results have shown promising performance compared with the results of using other image compression approaches.
Solid tidal friction in multi-layer planets: Application to Earth, Venus, a Super Earth and the TRAPPIST-1 planets
Authors: Bolmont E. , Breton S. N. , Tobie G. , Dumoulin C. , Mathis S. , Grasset O.
Published: October 2020

With the discovery of TRAPPIST-1 and its seven planets residing within 0.06 au, it is becoming increasingly necessary to carry out correct treatments of tidal interactions. The eccentricity, rotation, and obliquity of the planets of TRAPPIST-1 do indeed result from the tidal evolution over the lifetime of the system. Tidal interactions can also lead to tidal heating in the interior of the planets (as for Io), which may then be responsible for volcanism or surface deformation. In the majority of studies aimed at estimating the rotation of close-in planets or their tidal heating, the planets are considered as homogeneous bodies and their rheology is often taken to be a Maxwell rheology. Here, we investigate the impact of taking into account a multi-layer structure and an Andrade rheology in the way planets dissipate tidal energy as a function of the excitation frequency. We use an internal structure model, which provides the radial profile of structural and rheological quantities (such as density, shear modulus, and viscosity) to compute the tidal response of multi-layered bodies. We then compare the outcome to the dissipation of a homogeneous planet (which only take a uniform value for shear modulus and viscosity). We find that for purely rocky bodies, it is possible to approximate the response of a multi-layer planet by that of a homogeneous planet. However, using average profiles of shear modulus and viscosity to compute the homogeneous planet response leads to an overestimation of the averaged dissipation. We provide fitted values of shear modulus and viscosity that are capable of reproducing the response of various types of rocky planets. However, we find that if the planet has an icy layer, its tidal response can no longer be approximated by a homogeneous body because of the very different properties of the icy layers (in particular, their viscosity), which leads to a second dissipation peak at higher frequencies. We also compute the tidal heating profiles for the outer TRAPPIST-1 planets (e to h).
An adapted filter function for density split statistics in weak lensing
Authors: Burger Pierre , Schneider Peter , Demchenko Vasiliy , Harnois-Deraps Joachim , Heymans Catherine , Hildebrandt Hendrik , Unruh Sandra
Published: October 2020

Context.The density split statistics in weak gravitational lensing analyses probes the correlation between regions of different (foreground) galaxy number densities and their weak lensing signal, which is measured by the shape distortion of background galaxies.

Aims.In this paper, we reconsider density split statistics, by constructing a new angular filter function that is adapted to the expected relation between the galaxy number density and shear pattern, in a way that the filter weighting the galaxy number density is matched to the filter that is used to quantify the shear signal.

Methods.We used the results of numerical ray-tracing simulations, specifically through the Millennium Simulation supplemented by a galaxy distribution based on a semi-analytic model, to construct a matched pair of adapted filter functions for the galaxy density and the tangential shear signal. We compared the performance of our new filter to the previously used top-hat filter, applying both to a different and independent set of numerical simulations (SLICS, cosmo-SLICS).

Results.We show that the adapted filter yields a better correlation between the total matter and the galaxy distribution. Furthermore, the adapted filter provides a larger signal-to-noise ratio to constrain the bias between the total matter and the galaxy distribution, and we show that it is, in general, a more sensitive discriminator between different cosmologies, with the exception of cosmologies with very largeσ8values. All analyses lead to the conclusion that our adapted filter should be favoured in future density split statistic works.
TDCOSMO
Authors: Birrer S. , Shajib A. J. , Galan A. , Millon M. , Treu T. , Agnello A. , Auger M. , Chen G. C.-F. , Christensen L. , Collett T. , Courbin F. , Fassnacht C. D. , Koopmans L. V. E. , Marshall P. J. , Park J.-W. , Rusu C. E. , Sluse D. , Spiniello C. , Suyu S. H. , Wagner-Carena S. , Wong K. C. , Barnabè M. , Bolton A. S. , Czoske O. , Ding X. , Frieman J. A. , Van de Vyvere L.
Published: October 2020

The H0LiCOW collaboration inferred via strong gravitational lensing time delays a Hubble constant value of H0 = 73.3−1.8+1.7 km s−1 Mpc−1, describing deflector mass density profiles by either a power-law or stars (constant mass-to-light ratio) plus standard dark matter halos. The mass-sheet transform (MST) that leaves the lensing observables unchanged is considered the dominant source of residual uncertainty in H0. We quantify any potential effect of the MST with a flexible family of mass models, which directly encodes it, and they are hence maximally degenerate with H0. Our calculation is based on a new hierarchical Bayesian approach in which the MST is only constrained by stellar kinematics. The approach is validated on mock lenses, which are generated from hydrodynamic simulations. We first applied the inference to the TDCOSMO sample of seven lenses, six of which are from H0LiCOW, and measured H0 = 74.5−6.1+5.6 km s−1 Mpc−1. Secondly, in order to further constrain the deflector mass density profiles, we added imaging and spectroscopy for a set of 33 strong gravitational lenses from the Sloan Lens ACS (SLACS) sample. For nine of the 33 SLAC lenses, we used resolved kinematics to constrain the stellar anisotropy. From the joint hierarchical analysis of the TDCOSMO+SLACS sample, we measured H0 = 67.4−3.2+4.1 km s−1 Mpc−1. This measurement assumes that the TDCOSMO and SLACS galaxies are drawn from the same parent population. The blind H0LiCOW, TDCOSMO-only and TDCOSMO+SLACS analyses are in mutual statistical agreement. The TDCOSMO+SLACS analysis prefers marginally shallower mass profiles than H0LiCOW or TDCOSMO-only. Without relying on the form of the mass density profile used by H0LiCOW, we achieve a ∼5% measurement of H0. While our new hierarchical analysis does not statistically invalidate the mass profile assumptions by H0LiCOW – and thus the H0 measurement relying on them – it demonstrates the importance of understanding the mass density profile of elliptical galaxies. The uncertainties on H0 derived in this paper can be reduced by physical or observational priors on the form of the mass profile, or by additional data.
Separation between RR Lyrae and type II Cepheids and their importance for a distance determination: the case of omega Cen
Authors: Braga V. F. , Bono G. , Fiorentino G. , Stetson P. B. , Dall’Ora M. , Salaris M. , da Silva R. , Fabrizio M. , Marinoni S. , Marrese M. P. , Mateo M. , Matsunaga N. , Monelli M. , Wallerstein G.
Published: October 2020

The separation between RR Lyrae (RRLs) and type II Cepheid (T2Cs) variables based on their period is debated. Both types of variable stars are distance indicators, and we aim to promote the use of T2Cs as distance indicators in synergy with RRLs. We adopted new and existing optical and near-infrared (NIR) photometry ofωCen to investigate several diagnostics (color-magnitude diagram, Bailey diagram, Fourier decomposition of the light curve, and amplitude ratios) for their empirical separation. We found that the classical period threshold at one day is not universal and does not dictate the evolutionary stage: V92 has a period of 1.3 days but is likely to be still in its core helium-burning phase, which is typical of RRLs. We also derived NIR period-luminosity relations and found a distance modulus of 13.65 ± 0.07 (err.) ± 0.01 (σ) mag, in agreement with the recent literature. We also found that RRLs and T2Cs obey the same period-luminosity relations in the NIR. This equivalence provides the opportunity of adopting RRLs+T2Cs as an alternative to classical Cepheids to calibrate the extragalactic distance scale.
Changing-look active galactic nuclei: close binaries of supermassive black holes in action
Authors: Wang Jian-Min , Bon Edi
Published: October 2020

Changing-look active galactic nuclei (CL-AGNs) as a new subpopulation challenge some fundamental physics of AGNs because the timescales of the phenomenon can hardly be reconciled with accretion disk models. In this Letter, we demonstrate the extreme case: close binaries of supermassive black holes (CB-SMBHs) with high eccentricities are able to trigger the CL transition through one orbit. In this scenario, binary black holes build up their own mini-disks by peeling gas off the inner edges of the circumbinary disk during the apastron phase, after which they tidally interact with the disks during the periastron phase to efficiently exchange angular momentum within one orbital period. For mini-disks rotating retrograde to the orbit, the tidal torque rapidly squeezes the tidal parts of the mini-disks into a much smaller radius, which rapidly results in higher accretion and short flares before the disks decline into type-2 AGNs. Prograde-rotation mini-disks gain angular momentum from the binary and rotate outward, which causes a rapid turn-off from type-1 to type-2. Turn-on occurs around the apastron phase. CB-SMBHs control cycle transitions between type-1 and type-2 with orbital periods but allow diverse properties in CL-AGN light curves.
Research progress of low-temperature heat recovery technology in sulfuric acid production
Authors: Zong Jianfang , Sun Liang , Guo Huiting , Fang Fei
Published: October 2020

Low-temperature waste heat refers to the sum of the heat degraded and transferred to the dry absorption process after the high- and medium-temperature heat is recovered in the conversion process in the conventional sulfuric acid production plant, as well as the sulfuric acid formation heat, steam condensation heat and sulfuric acid dilution heat generated in the dry absorption process. It is of great practical significance to rationally develop and utilize the low-temperature waste heat. This paper introduces the development of traditional waste heat recovery technology and low-temperature heat recovery technology for sulfur-based sulfuric acid production. It also expounds the principle, process technology and main equipment of developing low-temperature heat recovery technology for sulfuric acid production plants at home and abroad, and summarizes the low-temperature heat recovery technology for sulfuric acid production plants.
Exergy analysis of the multi-stage slag waste heat recovery system
Authors: Duan Wenjun , Lv Xiaojun , Wang Zhimei , Zhao Dan
Published: October 2020

Based on the black-box model, this paper analyzed the multi-stage slag waste heat recovery system. The exergy efficiency, the exergy loss coefficient and the exergy loss rate were adopted as evaluation indexes to investigate the energy consumption and the weakness of the system. Meanwhile, the performance of waste heat recovery was analyzed by comparing the comprehensive exergy efficiency between the system and other conventional waste heat recovery methods. The results showed that the comprehensive exergy efficiency of the system reached 75.75%, which was much higher than other methods, and the weakness of the system was the subsystem of waste heat boiler. In general, the system recovered the slag waste heat effectively and converted coal to clean syngas through gasification reaction, which had incredible potential in energy saving, emission reduction and consumption reduction.
Electricity Consumption Forecast of Energy Saving Monitoring and Management Platform based on Exponential Smoothing Model
Authors: Wang Hongrui , Wei Ran
Published: October 2020

With the development of computer technology and Internet technology, more and more energy saving monitoring and management platform systems have been established. The energy saving monitoring and management platform has incomparable advantages in automation and real-time performance compared with traditional manual management. After a long time of operation, the energy saving monitoring and management platform has accumulated a lot of data. Due to various reasons, there is a lack of data in the process of collecting energy consumption, which affects the overall operation effect of the system. Based on the operation of an energy saving monitoring and management platform in a university in north China, this paper analyzes the data of building power consumption accumulated in recent years. This paper selects the typical metering branch data, establishes the exponential smoothing model, predicts the daily power consumption and analyzes the prediction results compared with the actual value to verify the effect of the prediction model. At the same time, it also provides a reference for the data prediction of energy conservation supervision platform of other universities.
Simulation investigation of ocean motion on small reactor based on modified system code
Authors: Li Dong , Peng Cheng , Hao Rao
Published: October 2020

Offshore nuclear small reactor is a promising research direction during recent years. In order to carry out system simulation and safety analysis under accident conditions for marine reactors, the classic thermal-hydraulic system analysis code RELAP5 is modified by taking heaving, inclining and rolling motion into consideration in this paper. Additional forces are added to the momentum equation for heaving and rolling, and control volume coordination are transformed for inclining and rolling. Then, a simplified small reactor with two loops is simulated by the modified code and the effect of ocean motion is investigated. Generally, heaving leads to the periodic fluctuation of mass flow rate, inclining would cause the decrease of total mass flow through the core, and the effect of rolling is more complex. Simulation analysis is also performed on two design basis accident LOCA and LOFA in this study. Safety related conclusions are obtained about the impacts of various ocean motion.
Application of the dynamic FMEA in the reliability analysis of DCS
Authors: Yankai Li , Xu Wang , Meng Lin
Published: October 2020

Digital distributed instrumentation and control system (DCS) is critical to the safety of nuclear power plants (NPPs). Static analysis methods developed from analog control system are not applicable to DCS due to its enhanced dynamic interactions and complex structure of hardware/software/firmware. The enhanced dynamic interactions of DCS include both sequence and timing factors, which are hardly modelled in the traditional Failure Mode and Effect Analysis (FMEA). In this study, dynamic FMEA (DFMEA) method based on simulation technology is put forward for the design and review of DCS in NPP. DFMEA based on real DCS hardware and software is developed to reveal the dynamic failure paths and failure modes. The results of DFMEA can well support the establishment of the dynamic fault tree/event tree in the review of NPP DCS, which reduces the dependency on the analyst’s experience significantly.
Acoustic Evaluation of Fishery Resources in Seawater Reservoir and Water-Intake Open Channel of Taishan Nuclear Power Plant
Authors: Wei MENG , Xiaolin LIU , Yong TANG , Shuai WANG , Jinfei ZHANG
Published: October 2020

The CGN Taishan NPP seawater storage is a land-sealed type and is connected to the open water intake channel of Dajin Island in the open sea through a subsea tunnel. Due to the impact of large-scale facility aquaculture in the nearby seas, fish spawning grounds have been formed in this area, and fish breeds faster. A large number of fish have impacted on safe operation of nuclear power. In response to this situation, this study conducted acoustic navigation surveys of fish resources in most waters of the “Sea Reservoir” and “Water intake channel”, using broadband scientific fish finder system (EK80, 120kHz, 200kHz) produced by Norwegian Simrad Company. Evaluation of acoustic resources using echo integration method. The survey scope of seawater storage in this survey is from the entrance to the first barrier (around a distance of 760m) and from the first barrier to a second barrier (around a distance of 220m); the survey distance of the water intake channel is about 1460m. From the echo image, it can be found that the zooplankton in the sea reservoir is much smaller than the water intake channel, and the fish size of the water intake channel is much larger than that of the sea channel.Acoustic data was processed and analyzed using Echoview software to calculate the average SV and detect the strength of the single target. The results show that in the survey area of the Taishan Nuclear Power Plant Hai Reservoir, the total number of fish is about 1.38 million, the total weight is about 13.6 tons, and the fish with a body length of less than 20cm is the majority, and there are fewer large-sized fish; The total resources in the survey area is about 47 tons, with a total number of 27 million, and has a high density.
Sensitivity analysis of several operational parameters on gas temperature deviation in a tangential firing boiler
Authors: Yu Cong , Yu Haiquan , Hu Wenpeng , Wu Hanlin
Published: October 2020

In this work, an integrated numerical model combining combustion and fluid heating was established for a 660 MW coal-fired boiler. To validate the accuracy of the developed model, related experiment was also conducted, and shows that the relative errors (REs) of several predicted parameters on both flue-gas side and water-steam side of the boiler are less than 7 %, which meets the requirement of analysis. The results indicate that the effect of SOFA tilt angle on gas temperature deviation (GTD) is greatest, and that of SOFA’s proportion follows; while GTD presents a smallest sensitivity to the concentration of O2. This is because O2 concentration mainly affects the average value of the gas temperature, but barely changes its distribution. By contrast, altering SOFA’s tilt angle and its proportion directly varies the shape, location, and area of the high-temperature and low-temperature regions at the entrance profile of the horizontal crossover pass, so these two factors play a more important role in the variation of GTD.
Renovation Measures for Energy-saving Skin of Existing Buildings
Authors: Tong Hao , Chen Kai
Published: October 2020

As an important part of internal and external connections, the building skin can not only beautify the appearance of the building, but also improve the energy-saving performance of the building. This article aims to sort out the specific measures of skin energy-saving renovation from three aspects: the renovation of the peripheral protection structure, the energy-saving renovation of windows and the addition of shading measures, and analyses them in combination with typical renovation cases.
Catalytic Dehydrogenation of Methylcyclohexane by Pt Nanoparticles Supported on Nitrogen doped Carbon
Authors: Wang Jian , Fan Shiguang , Xu Xuan , Yun Huiru , Liu He , Wang Zongxian
Published: October 2020

Pt nanoparticles supported on nitrogen doped carbon (Pt/CN) catalysts with different surface areas were obtained and characterized by transmission electron microscope （TEM） and brunner-emmet-teller （BET）. The characterized results showed that Pt nanoparticles dispersed uniformly on the support surface, and the surface area of the Pt/CN catalyst increased with the increase of annealing temperature. Subsequently, the catalytic performance of Pt/CN catalysts for methylcyclohexane dehydrogenation was studied. The activity of Pt/CN catalysts in methylcyclohexane dehydrogenation increased with the increase of the surface area, Pt/CN-1000 catalyst has the largest surface area and the highest catalytic activity, with the methylcyclohexane conversion of 99% and the TOF value of 424.78 h-1 at 180 ℃ for 150 minutes.
Study on volcanic reservoir characteristics of Yingcheng Formation in Xudong area of Xujiaweizi fault depression
Authors: Jia WANG , Yue ZHOU
Published: October 2020

Types of deep reservoir rich in Yingcheng formation of Xudong area in Xujiaweizi fault depression, the study of volcanic rocks of Yingcheng formation in the main, using the date of core, logging, oil test, from lithology, lithofacies and physical properties to study volcanic reservoir characteristics. The main lithology of volcanic reservoir in Yingcheng formation of Xudong area include rhyolite, rhyolitic tuff, rhyolitic tuff fused, rhyolitic breccia and rhyolitic tuff breccia. In accordance with lithology combination of features, volcanic facies can be divided into volcanic explosive facies, volcanic effusive facies and volcanic sedimentary facies. The main types of porosity have air vent of primary pore, remnants pores of air vent filled after, cracks, micro-cracks and feldspar corrosion hole of secondary porosity, volcanic ash corrosion hole, micro-pore produced by rhyolitic glass from glass off in spherules rhyolite, quartz crystal chip corrosion hole, and so on. Through studying the ratio of reservoir and formation for a single well, the frequency distribution of reservoir thickness, production capacity situation and pool-forming regularity, Xudong area can be divided into three reservoir development zone, so we will find out the most favorable reservoir development zone, then it can play a guiding role for the next step of the exploration deployment.
Study on Prevention of Gas Channelling of Acid-resistant Gel Foam in CO2 Flooding of Low Permeability Reservoir
Authors: LIU Zhaoxia , GAO Ming , ZHANG Shanyan , LIU Wanlu
Published: October 2020

With the shortage of recoverable reserves in conventional oil reservoirs, the development of low-permeability oil reservoirs has received more and more attention. The oil recovery of low-permeability reservoirs can be significantly improved by CO2 flooding, as it can effectively supply formation energy. CO2 flooding is an effective technology for increasing oil production in low-permeability reservoirs. However, because of the heterogeneity of the reservoir and the effect of natural fractures, CO2 gas channelling easily occurs during CO2 flooding, seriously reducing CO2 flooding effect. In this study, the gas channelling technology of acid-resistant gel foam was investigated. Preferred acid-resistant gel foam system formula was found as 0.1% by mass of AOS foaming agent with 0.3% to 0.4% by mass of instant HPAM polymer and 1% to 2% by mass of water-soluble phenolic resin crosslinking agent. This system still has a good foaming ability and blocking performance under at pH=2 and a salinity of 10×104 mg/L. After 60 days of aging under oil reservoir conditions, there is no obvious water separation, and the plugging strength retention rate reached more than 60%. The gel foam channelling system can be applied to highly heterogeneous and low permeability reservoirs with a permeability gradient higher than 14 and can increase the recovery rate by more than 20% based on the CO2 flooding. Acid-resistant gel foam channelling technology can effectively inhibit CO2 gas channelling and improve CO2 flooding effect in low permeability reservoirs.
Research and Mechanism of Two-step Preparation of Acetamide from Microalgae under Hydrothermal Conditions
Authors: Jiang Jikang , Ye Haixia , Zhou Jingfei , Wang Chenlu , Shen Zheng , Zhang Yalei
Published: October 2020

A two-step synthesis of acetamide under hydrothermal condition from microalgae, is presented. results showed that the best yield of acetamide and selectivity of acetic acid were 9.5 % and 60.1 % at 320 ℃ for 8 min with a NH3 supply of 30. Algae such as spirulina, cyanobacteria and autotrophic chlorella could also acquire acetamide, and lactic acid was found to be an important intermediate during the exploration of reaction pathways. These results demonstrated that it is possible to develop a process for conversion of microalgae biomass into acetamide.
Design of Marine High Power Wireless Charging System
Authors: Chen Yajie , Pan Zhiqiang , Ni Ming , Gao Haibo , Pan Zhao , Huang He , Zhu Yihang
Published: October 2020

With the application of new energy ships equipped with large-capacity batteries/ultracapacitors in oceans, inland rivers and lakes, the need for high-power wireless charging systems has become increasingly urgent. Based on the analysis of the characteristics of ship charging operation, this paper selected the structure of loosely coupled transformer and introduces its core technology. Then the basic principle of the wireless charging system for the ship is introduced, and the scheme of 1.2 MWwireless charging system is designed according to the specific application.2.5
Study on two-stage air-recirculation ammonia stripping process for membrane concentrate in livestock and poultry breeding
Authors: Junjie Chen , Hongguang Zhu , jin Ji
Published: October 2020

Aiming at the problems of the subsequent treatment of the biogas liquid membrane concentrate and the large alkali consumption of the traditional stripping process, a two-stage closed-cycle ammonia stripping process was designed, and the two-stage air-recirculation ammonia stripping process was used to treat the biogas liquid membrane concentrate. Studies have shown that in the first stage of ammonia stripping, when the gas-liquid ratio is 3600, the pH of the membrane concentrate liquid after the closed loop treatment reaches the maximum value of 8.75, and the alkalinity is also reduced from the initial 8150 to 6615.After the primary stripping is completed, the pH of the membrane concentrate can be quickly increased by adding alkali to meet the normal ammonia stripping conditions for the secondary stripping tower. When the liquid ratio of the secondary stripping tower is 3600, the temperature is 40°C, and the CaO dosage is 25g/L, the removal rate of ammonia nitrogen is 86%. Adding a first-stage tower blowing off, the CaO dosage is reduced by 5g/L.
Pt Nanoparticles Supported on Nitrogen doped Carbon as an Efficient Catalyst for Decalin Dehydrogenation
Authors: Yun Huiru , Li Zhuo , Fan Shiguang , Wang Jian , Liu He
Published: October 2020

A novel Pt/CN catalyst was synthesized by sodium borohydride treatment. The physical and chemical properties of Pt/CN catalyst were characterized by X-ray diffraction (XRD), brunner-emmet-teller (BET), transmission electron microscope (TEM) and High-resolution transmission electron microscopy (HRTEM). The characterized results showed that the catalyst has a high specific surface area, mesoporous structure and the mean size of Pt nanoparticles is 2.59 nm. Subsequently, the catalytic performance of Pt/CN catalyst for decline dehydrogenation was studied. Pt/CN catalyst exhibited excellent performance in decalin dehydrogenation with the conversion of decalin was 30.70%, and the selectivity of naphthalene was 90.86% at 200 ℃ for 150 minutes. When the reaction temperature increased to 210 ℃, the conversion of catalyst increased to 52.02%, and the selectivity of naphthalene reduced to 90.21%. The possible reason may be attributed to the difficulty in converting decalin to tetralin. This paper would provide a novel method for the synthesis of efficient dehydrogenation catalyst of decalin..
Forecasting method of electric vehicle load time-space distribution considering traffic distribution
Authors: Liu Weidong , Li Lei , Xie Qin , Li Dan , Zhang Jing
Published: October 2020

The main work of this paper is to establish an electric vehicle(EV) load forecasting model based on road network traffic distribution for urban and inter-city transportation networks. This paper established a road network model considering the traffic impedance for the EV load forecasting of the urban fast charging network, and studied the prediction method of the time-space distribution of EV charging demand in the fast charging mode .Based on the expressway, the method for predicting the time-space distribution of EV load in the inter-city fast charging network is studied, and a time-space distribution load forecasting model is established. Based on the time-space distribution of traffic flow, combined with EV charging characteristics and travel routes, load simulation is performed. By constructing a prediction method for the time-space distribution of EV charging demand in the fast charging mode, it provides theoretical and methodological support for the research of time-sharing and segmented metering and charging strategies for EV fast charging stations,, and provides an important reference for the development of EV charging facilities operating cost benefits, economic performance indicators and calculation models under fast charging mode, which are of great significance to promote the popularization and application of EV fast charging modes.
Bolt loose judging device for offshore wind turbine
Authors: Fei Wang , Jun Qu
Published: October 2020

For the problem of bolt loose in the long-term operation of offshore wind turbine, we proposed a bolt loose judging device for offshore wind turbine. The bolt loose judging device for offshore wind turbine included vibration sensor, signal receiving and transmitter, CCD sensor, data analyzer, power supply, the communication line and the power supply line. The combination of data analyzer and CCD sensor was used to analyze whether the prefabricated symbols on the bolts change, so as to judge whether the bolts are loose. The whole system (except vibration sensor) has been in standby and dormant state at ordinary times, which is more simple and reliable under the harsh conditions at sea.
Demand contracting strategy for charging stations based on load forecasting
Authors: Chen Fang , Zeyu Liu , Haojing Wang , Yi Zhao , Shanshan Shi , Qiang Gui
Published: October 2020

Since the stochasticity of the charging of electric vehicles (EVs) may bring impact to the grid, there is a high possibility that the demand charge will be applied to charging stations. Therefore, a load-forecasting-based demand contracting strategy is proposed for charge stations in this paper. A stochastic optimization model is established by regarding the maximal demand as a stochastic parameter, and the object of the model is to minimize the expectation of demand charge, and the analytic solution is derived. To obtain the distribution of actual maximal demand, a Monte-Carlo-based charge load forecasting method is proposed. It gives the distribution of the daily maximal demand, based on which the distribution of monthly maximal demand is also derived. The case study illustrates the feasibility and the validity of the proposed strategy.
Analysis of the spatial effects of inter-provincial air pollution in China
Authors: Yanyan Zhang
Published: October 2020

Air pollution is a hot environmental issue that people have continued to pay attention to in recent years, and the government has spared no effort to strengthen its prevention. Haze is the result of the interaction between specific climatic conditions and human activities. Economic development and population agglomeration are important causes of smog on a large scale. Based on China’s provincial haze pollution PM2.5 data from 2003 to 2017, Moran’s I index and LISA scatter plot were used to analyze the spatial correlation of haze pollution. The results show that there is a positive spatial correlation between China’s provincial haze pollution. Therefore, the problem of air pollution is a regional problem, and it is necessary for each region to strengthen regional joint prevention and control according to location conditions, natural conditions and economic conditions, and contribute to the prevention and control of smog.
Is It Possible for Pigou Tax and Coase Scheme Working Together? A New Externality Elimination Framework from Relation and Network Perspective
Authors: Jiang Yanjie , Du Zhuoqun , Wu Peilin
Published: October 2020

The extensive use of traditional fossil energy will produce huge environmental or health negative externalities. When it refers to the case of Private Passenger Vehicle (PPV), it exhausts a large amount of air pollutants, which will cause serious health damage to people. Based on the relation and network perspective, examining the traditional externality elimination mechanism-Pigou Tax and Coase scheme, can better summarize their advantages and disadvantages, and propose a new externality elimination framework accordingly. The research poses a new externality elimination framework that combines the advantages of them. It can not only realize the compensation for the health damaged under the Pigou tax, but also make full use of the market disclosure advantage of the Coase scheme for infringement preferences. The research first explains the framework of externality elimination based on relation and network perspective, and reveals that the essence of externality elimination is to change the asymmetric relation of interests into a symmetrical one. Then the study explains the property rights and pollution rights in the Coase scheme also based on relation and network perspective, and believes that property rights are to ensure no externality. Finally, using the social welfare maximization model, the Coase scheme pollution authority amount is included in the indirect utility objective function of a gasoline or new energy vehicle throughout its life cycle, and then the overall social welfare expected to purchase a car is investigated, in order to obtain the substitution relationship between the amount of authority and the amount of compensation, which plays a key role of the new externality elimination framework.
The combined effects of hydrothermal treatment and Na2S2O8/ CuFe2O4 magnetic oxidation on sludge dewaterability improvement
Authors: Chen Yonghao , Chen Dandan , Dou Yuhao , Song Min , Peng Feirong
Published: October 2020

Na2S2O8/CuFe2O4 addition and hydrothermal pretreatment were combined in this paper to ameliorate the dewatering performance (DP) of sludge with specific-resistance of filtration (SRF), time of capillary suction (CST), and water content (Wc) as well as water types investigated. The results shown the synergistic effect between Na2S2O8/CuFe2O4 addition and hydrothermal pretreatment and the DP of sludge reached to the best when the hydrothermal temperature was 150oC, the addition amount of Na2S2O8 was 0.08 mmol/g-VSS and the mass ratio of Na2S2O8/CuFe2O4 was 2.0. Through the analysis of water distribution, it was also demonstrated that the sludge structure was destroyed with the surface moisture released. All the results obtained shown the significant impact of the combined methods on ameliorating DP of sludge and promoting sludge recovery and utilization.
Design of identification and printing module circuit for garbage collection system based on Internet of things technology
Authors: Yan Qing , Jia Lianqin , Liu Qin , Cui Chengsheng
Published: October 2020

Under the premise of the implementation of waste classification in China, the public has designed a lot of garbage collection systems, but all of them have single use. Therefore, the author designs the identification and printing module, so as to expand the use of the garbage collection system.
Advances in remediation of heavy metal contaminated soil and water by Leersia hexandra Swartz
Authors: Qin Hui , Lin Hua
Published: October 2020

Heavy metal pollution is extremely harmful to human beings. Looking for an efficient and environmentally friendly treatment method is the focus of current research. Using plants to treat contaminated water and soil has proven to be an effective and environmentally friendly method. Leersia hexandra Swartz is a chromium hyperaccumulator, and it can also enrich copper and nickel. Since the super enrichment characteristics of Leersia hexandra Swartz were discovered, many scholars have poured into the research on Leersia hexandra Swartz. This article will give an overview of the current application status of Leersia hexandra Swartz’s purification of polluted water and soil, analyze the methods and principles used, and discuss the future development direction of Leersia hexandra Swartz’s plant remediation technology.
Research on the current situation of ultrafiltration combined process in treatment of micro-polluted surface water
Authors: Lou Yuying , Zhang Shoubin , Zhu Tong
Published: October 2020

At present, most of the source water of domestic urban water supply treatment plants is taken from micro-polluted surface water. With the further improvement of drinking water sanitation standards, the traditional “coagulation-sedimentation-filtration-disinfection” process cannot meet the requirements of the new standards. Ultrafiltration, as the core technology in the field of water treatment in the 21st century, is increasingly applied to water treatment due to its advantages of green efficiency, simple operation, small footprint, and high degree of automation. However, the use of ultrafiltration membrane alone has some problems such as substandard water quality and serious membrane pollution. Therefore, the combination of ultrafiltration and traditional water treatment technology to treat micro-polluted surface water has become the mainstream choice for treatment plants. This article mainly introduces the current research status of domestic ultrafiltration combined technology, trying to explore more reasonable and effective ways to apply ultrafiltration membranes in actual projects.
Ecological risk assessment of heavy metals in road dust based on improved potential ecological risk index: A case study in Zhengzhou, China
Authors: Zhu Huina , Zhang Liangbo , Zhao Hailiang , Zhang Baozhong , Chen Hanyu , Shi fan
Published: October 2020

In order to analyze the ecological risk of the heavy metals in road dust. The improved potential ecological risk index was established. In the improved method, the toxicity of different chemical speciations of heavy metals were considered. Since residual fraction of Cd are non-toxic in the improved method, the results of the improved method were much lower than the traditional method.The results showed that the total risks of 3# and 15# were medium risk. The highest risk appeared on14# with the value 337.49, which belonged to high risk, and the total risk of the other sampling sites were low risk. Therefore, 14# should be the primary control site. The improved method established in this study is more scientific.
Recovery of Cr(VI) from vanadium precipitated solution by precipitation with PbSO4
Authors: Minge Yang , Haoxiang Yang , Shenghui Tian , bin Hu , Changda Chang , Mingyu Wang , Xuewen Wang
Published: October 2020

The recovery of Cr(VI) from vanadium precipitated solution obtained by adding Ca(OH)2 into chromium-containing vanadate solution and ball milling was investigated by precipitation with PbSO4. It was found that Cr can be effectively precipitated from the solution by PbSO4. The precipitate is mixture of PbSO4 and PbCrO4.PbO. The concentration of Cr remained in the solution decreases from 2.360 g/L to 0.002 g/L by adding PbSO4 into vanadium precipitated solution according to PbSO4/Cr molar ratio 3.0 under pH 11.5 and stirring for 120 min at 30 °C. After filtration, the precipitates were leached in H2SO4-Na2SO4 system solution to obtain Na2Cr2O7 solution and the filtrate can be reused to leach the precipitate contain PbSO4 and PbCrO4.PbO.