bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Application of Item-based Collaborative Filtering Algorithms in MOOC
Authors: Lu Qirong , Xia Jiwei
Published: September 2019

In the learning process, the recommendation system can recommend learning resources that are in line with the learning situation of the learning objects and help the learning objects to learn more easily and naturally. By analyzing the characteristics of item-based collaborative filtering algorithm, this paper applies it to the recommendation system of mooc learning resources to avoid the possible defects of this algorithm, such as low performance and offline processing in other scenarios, and gives full play to its good real-time performance and high recommendation efficiency. By analyzing the log files of imooc, this paper obtains the learned learning resources of the learning objects in imooc, takes the first 80% data of historical records, obtains the recommended list of learning resources through recommendation algorithm, and then compares the data of the last 20% of historical records. Finally, the algorithm is optimized according to the accuracy of the recommendation algorithm in the experiment and the actual learning scene.
A Novel Method for Reconstructing Dynamic Bayesian Network
Authors: Yu Ying , Huang Hao , Lu Jianye , Yang Zhen , Yang Wenwen
Published: September 2019

Upon data renewal, a Bayesian network might need reconstruction. In this paper, a novel method, which is based on a proposition, is proposed for such reconstruct work of a kind of symptom--disease Bayesian network scored by a K2 soring function. The proof of the proposition for the method is given firstly, and later the performance of the method is illustrated with numerical examples.
Artificial Intuition Reasoning System (AIRS) and Application in Criminal Investigations
Authors: Liu Shuxia , He Ping
Published: September 2019

Intuition is a special function of human brain, and it is an urgent task to establish a reasoning system with intuitive characteristics in the field of artificial intelligence. The purpose of this paper is to establish a formal model of intuitive reasoning based on the analysis of the characteristics of intuitive reasoning in criminal investigation. At the same time, it provides an artificial intuition model for constructing inference machine of criminal investigation. First, a novel framework of intuitive reasoning system is established based on the principles of memory mapping and perceptual inversion. Secondly, according to the fuzzy perception of experience and knowledge, a formalized criterion which accords with humans intuitive reasoning is established, namely the intuitive characteristic index. Finally, the artificial intuition reasoning model is used to analyze a crime investigation case. The results show that the reliability of this artificial intuitive reasoning system is 85% in practical application, and this intuitive reasoning process is a learning system of experience and knowledge. If this intuitive reasoning system can simulate human brain’s intuitive reasoning after limited intuitive training and learning.
Research of Differential Privacy Protection on Social Network
Authors: Zhang Jian , Zhang Changlun , Chen Shihui , Wu Shupeng
Published: September 2019

Rapid development has been witnessed in social network. As a consequent, much more people are involved in getting it, sharing their own information to enlarge their social circle. In this paper, the security problem, which exists in privacy preserve in social network and process users’ private information via Differential Privacy Histogram Release is focused on. The method can process user’s privacy information on the premise of guaranteeing the availability of information, making the information released after publication different from the information before publication, thus making the user’s privacy information not leak. Shown by theoretical analysis and research results, safe release of private information can be guaranteed if processed by this method.
A Weak Centralized Consensus Mechanism with More Incentive Effects
Authors: Mu Yuxiang , Chen Wanghu , Liang Xiaoyan , Gao Yaqiong
Published: September 2019

In the blockchain system, the consensus mechanism not only helps the nodes maintain data consistency, but also has certain functions for token issuance and attack prevention. Aiming at the problems of low enthusiasm and weak centralization in Delegated Proof of Stake (DPoS), this paper proposes a weak centralization consensus mechanism with more incentive effect. We replace the voting link with opportunity verification mechanism, and make the voting link that affects the enthusiasm of nodes become the embodiment of their own rights and interests, so as to strive for the maximization of their own interests. And we also introduce the method of random guess to make the selection of representative nodes more random, so as to achieve the situation of weaker center. At last, combined with the existing problems, the paper analyses the feasible solution with this mechanism.
Neural Network Approach for Multiple-Class Classification
Authors: Wu Dengyi , Tu Chingsheng , Lee Shiejue , Wu Chihhung
Published: September 2019

Classification is a very important problem-solving technique. Given a set of attribute values about an object, a classifier determines which category the object belongs to. A classification task can be a binary or multiple classification; it can also be a single-label or multiple-label classification. Neural networks are an effective technique in the field of artificial intelligence. In this paper, we develop different schemes of neural networks for solving binary, multiple, single-label, and multiple-label classification problems. The ideas behind them are described in detail.
The Stage Model of Intelligent System Forensics
Authors: Zhao Ziyu , Wang Yongquan , Liao Genwei
Published: September 2019

With the rapid development of Internet, mobile communication is moving towards the 5G era, and the application of intelligent systems is in the ascendant. The corresponding intelligent system forensics has become one of the research highlights. By comparing the differences between intelligent system forensics and traditional electronic data forensics, this paper studies the specific content of intelligent system forensics, and proposes a stage model of forensics, which mainly included seven stages: formulation of forensics strategy, safe collection of media/equipment, equipment protection before laboratory forensics, preparation before laboratory forensics, development of laboratory forensics, reconstruction of the case process, and preservation of evidence. The model will be conductive to a more normalization process to improve the reliability, integrity and avoid misoperation of intelligent system forensics.
A integrated Navigation Filtering Method Based on Wavelet Neural Network
Authors: Tao Zhu , Gao Saisai , Huang Ying
Published: September 2019

Aiming at the problems of the difficulty to establish the model and the large data dimension for the traditional integrated navigation method, a method of using the wavelet neural network to directly predict the position and velocity error information is proposed. Get rid of the mathematical model establishment, void introducing new errors in the model establishment, and adopt multiple parallel networks to reduce the dimensionality of the data, which greatly reduces the amount of calculation. The Kalman filter is used as a reference for simulation experiment. The results show that the proposed method can effectively improve the accuracy and real-time performance of the integrated navigation system, and provides a new feasible path for combined navigation filtering.
Relaxation of Gene Network after Injection of Influenza Virus
Authors: Deng Shiguo , Ren Henggang , Yuan Qianshun , Yang Huijie
Published: September 2019

The relaxation of gene network after injection of influenza virus is investigated from the perspective of diffusion process. The key idea is to separate each snapshot network into communities, and the identification number of the community in which every node occurs is used to represent the state of the node in this snapshot. From a series of snapshots of network one can construct the trajectories for all the nodes, which form an ensemble. The relaxation is then described by the division and fusion of the communities. It is found that the gene networks for healthy individuals evolves regularly, while that for the individuals affected by influenza virus in a chaotic way.
An Improved Infrared Image Contrast Enhancement Method
Authors: Wang Yuanbin , Zhang Jian
Published: September 2019

Aiming at the characteristics of infrared image, such as concentrated gray level distribution, low contrast and poor resolution, the paper proposes an improved infrared image enhancement algorithm. Firstly, the original image is filtered by adaptive median filtering method, then platform histogram equalization and gamma transformation are performed on the filtered image to improve the overall contrast of the image. At the same time, the filtered image is performed by Laplacian sharpening to get the edge information of the image. Finally, we obtained an enhanced infrared image by weighted combination of gamma transformation and Laplacian sharpening. Experiment shows that target contrast and average brightness are enhanced by the proposed algorithm, furthermore, the overall information is preserved and the edge information of the image is obtained, which improves the visual effect.
Research on Die Casting Process of Magnesium Alloy Motorcycle Wheel Based on New Engineering Construction
Authors: Zhang Zhanling , Zhang Yanqin , Zhang Hui , Pan Aiqiong , Liu Jun
Published: September 2019

Magnesium alloy forming technology is a hot spot in the world. This paper introduces the application of AM60B magnesium alloy and die casting technology in the forming of motorcycle wheel casting, and the test and analysis of die casting process, Finally, qualified magnesium alloy wheel castings are produced. the selection of die casting process parameters was 680 ∼ 700°C, the casting temperature of 240 ∼ 280°C, and the pressure ratio between 180 ∼ 200MPa and the holding time was 20 ∼ 25s. Under the condition of optimum technological parameters, obtained by casting the mechanical properties testing results: σb=218∼227MPa, HBS=66∼71, δ5=9.8 ∼10.7% and ak = 17.5 * 104∼18.7 * 104j / m2. The practice has proved that the die casting technology is a suitable process for magnesium alloy wheels, and it has reference value for the mass production of large area magnesium alloy casting.
Data Acquisition and Analysis of Photocell Characteristics and Its Application in Switch Circuit Control
Authors: Wang Lingbo
Published: September 2019

Photocells which produce a voltage and supply an electric current when illuminated have been widely used. The basic characteristics of the photocell were tested and analysed through experiments by an optical control experimental platform, such as short circuit current, open circuit voltage, illumination characteristic, volt ampere characteristic, load characteristic, and spectral characteristic. The experimental results are in agreement with the theoretical analysis. The light control switch circuit was realized by using photocell. In this way, the principles and operation of photocell can be well comprehended.
A Comparison of Two Methods for Determining the Genome Size of Taimen
Authors: Yang Guiqiang , Zhang Liying , Wang Zhanquan , Li Wentong , Yuan Ding
Published: September 2019

To compare the two methods for determining the genome size of Taimenes (Hucho taimen). The present study determined genome size (or C- values) of 30 individuals of Taimenes by the method of PI (propidium iodide) and DAPI (4’,6-diamidino-2-phenylindole), through the flow cytometry, using chicken erythrocyte DNA content as a standard. The result showed that (1) With the method of PI and DAPI through the flow cytometry, DNA content in blood erythrocyte was 5.65±0.25 pg•2C-1 and 5.04±0.12 pg•2C-1(Fig. 1 and Fig. 2), and genome size (Gb) were 2.70 ± 0.12 Gb and 2.41 ± 0.06 Gb. By Independent-Samples T Test, the genome size (Gb) of blood erythrocyte determined by PI was significantly greater than that determined by DAPI(Table 1). (2)Several of the main support salmonids were clustered by furthest neighbor of any two C-values with the measure of euclidean distance. From the Fig. 3, we found that taimen and fine scale (Brachymystax lenok)first clustered into the same subgroup 1, brook trout (Salvelinus fontinalis) and Atlantic salmon (Salmo salar) clustered into the same sub-group 2, rainbow trout (Oncorhynchus mykiss) and pelyad (Coregonus peled) clustered into the same sub-group 3, Subgroup 1 and subgroup 2 firstly clustered into the same team, then come together with subgroup 3. The result indicates that (1) PI method can more accurately reflect the distribution of DNA content in blood erythrocyte of taimen, and more accurate prediction genome size of taimen.(2)Cluster analysis of C-values of several salmons may be related to their respective origin distribution and the filter feeding characteristics of Pelyad.
Safety Valuation of Military Aviation Control System Based on Cloud Model
Authors: Ye Zelong , Wen Xiangxi , Wu Minggong , Li Jiawei , Qiu Shidai
Published: September 2019

At present, the flight training, army operation increase constantly, the army ATC faces rigorous challenges. The safety evaluation on ATC can enhance the control effect and guarantee fly safety. In this paper, an evaluation index system is established based on ‘human factor, machine factor, environment factor and management factor’. On the basis of AHP and cloud model, the safety evaluation model is built. To validate the model, an experiment is operated, the result is accord with the real situation, which proves the scientifically and feasibility of this model.
The simulation of three crossroad traffic queueing systems using petri nets and colored petri nets program
Authors: Wicaksono A , Rudhito M A
Published: September 2019

This research aims to develop a simulation of traffic flow at the crossroads, that’s Monjali, Kentungan and Gejayan crossroads in Yogyakarta with and without underpass. The simulation using petri nets and colored petri nets programs. We assume that each crossroad has the same density, and we look that the traffic flow just went one way. The results of the study show that the queuing system for three traffic intersections can be modeled using petri nets. Furthermore, a queue simulation can be carried out with the help of a colored petri nets program. Simulation results indicate a buildup at certain junctions without underpasses and with underpasses
Driver Parking Behaviour: An Observational and Experimental Intervention Study
Authors: Najihah Mad Rosni Nurul , Fadzil Jobli Ahmad , Neging Maureen
Published: September 2019

Illegal parking has become a major problem in Malaysia especially in urban area due to the increased traffic volumes and limited parking space. When the parking facilities are limited, driver factor thus has a significant effect on the formation of traffic congestion. Extensive work has been conducted to address this issue, however most studies did not incorporate the impact of driver behaviour at limited parking condition whereas it is understood that “cruising for parking” at limited parking facilities has a very strong influence on the road traffic jams. Thus, objectives of this study are to analyse drivers’ personality traits which focus on consideration and selfishness traits; and to investigate drivers’ personality traits and their impact on driver parking behaviour in Kuching, Sarawak. Analyzation of driver parking behaviour was based on observational study of driver, vehicle, and situational variables. Experimental intervention then conducted to different age groups of drivers. They were asked to respond to questions that related to the driver parking behaviour characteristic. Analyses of the data reported in this study revealed that most of the drivers are considerate enough but they become a selfish person when confront with difficult situation at the parking space and their action sometimes are susceptible to illegal parking. The findings significantly beneficial to the traffic engineer, policy maker and researcher in enhancing parking control and management system.
Potential Use of Locally Available Filter Media in a UAFB Reactor Coupled with Natural Treatment in Soybean Industry Wastewater Treatment
Authors: Nayono Satoto E. , Purwantoro Didik
Published: September 2019

Many food industries in developing countries cannot afford proper wastewater treatment and directly discharge their wastewater into surface water bodies causing several problems such as aesthetical, health and environmental problems. A new approach for low-cost wastewater treatment which is reliable, allows nutrients and energy recovery should be promoted. One of the alternative wastewater treatment technologies is anaerobic wastewater treatment which offers a number of advantages such as low energy requirement, low production of sludge and the possibility of energy recovery. As one of the disadvantages of using anaerobic method is that the effluent usually does not meet the authority’s regulation to be discharged directly into water bodies, to further treat the effluent in order to meet the standard, the up flow anaerobic fixed-bed reactor will be coupled with a ‘natural treatment’. This paper presents preliminary results of a research which has the main goal to examine the of several locally available materials as packing media in UAFB reactor and the appropriate vegetations for constructed wetland and/or macrophyte pond. Additionally, potential energy recovery from soybean wastewater is also calculated.
Influence of groundnut shell ash on the properties of cement pastes
Authors: Usman Jamilu , Yahaya Nasiru , Mohammed Mazizah E
Published: September 2019

This paper presents the effect of groundnut shell ash (GHA) on the properties of cement paste. Cement pastes containing GHA as cement replacement in different proportions up to 50% by weight were prepared. At fresh state, the consistency and setting times of the pastes were checked, while at hardened state, soundness and compressive strength of the pastes were determined. In addition, the microstructure of the hardened paste was investigated using the Fourier Transformed Infrared (FTIR) technique. The results show that GHA increased water demand and delayed setting times, but improved soundness of cement paste. Moreover, compressive strength enhancement of hardened cement paste due pozzolanic reaction as evidenced by the microstructure analysis (FTIR) was observed with up to 10% GHA replacing cement. Thus, GHA is a good potential material for cement replacement in cement paste.
Preliminary Study on Properties of Oil Palm Shell Lightweight Concrete with Cockle Shell as Mixing Ingredient
Authors: Aris Shariza Mat , Carlos Philip Dick , Mohsin Sharifah Maszura Syed
Published: September 2019

Environmental pollution caused by the dumping of oil palm shell (OPS) from palm oil mill and cockle shell from cockle trade has initiated early exploration to discover the potential of these waste incorporated in concrete production. The present research investigates the effect of integrating crushed cockle shell as partial fine aggregate replacement on compressive strength and flexural strength of OPS lightweight aggregate concrete. A total of five mixes were prepared. OPS lightweight aggregate concrete containing 100% river sand was used as control specimen. Other mixes were produced by varying the percentage of crushed cockle shell by weight of sand. All specimens were water cured for 28 days before subjecting it to compressive strength and flexural strength. The finding shows the concrete exhibit strength increment when crushed cockle shell is added as partial fine aggregate replacement. Conclusively, crushed cockle shell has the potential to be used as mixing ingredient in OPS lightweight concrete production.
Utilization of Fly Ash in Construction
Authors: Ghazali Norhaiza , Muthusamy Khairunisa , Wan Ahmad Saffuan
Published: September 2019

In year 2016, Malaysia produce about 6.8 million tonnes of fly ash from six coal fired electric power station and this figure will increase due high demand of electric production. Fly ash is a waste product from the combustion of pulverized coal in electricity power plants and considered as a contributing factor for air, water and soil pollution that lead to human health problems and various geo-environmental issue. However, fly ash can be converted into valuable and useful product if properly utilized and many researches has been carried out in aim to increase the utilization of fly ash in various sectors especially in construction sector. In line with current economic conditions, all construction works required cost efficient with good quality of work. Therefore, fly ash is suitable to be used as an alternative raw material to enhance or replacing the existing construction material. In produce construction material many different industries and construction because it is oxide-rich material. The paper will be discussing the potential of managing waste of fly ash by utilizing it as construction materials.
Flexure Behaviour of Foamed Concrete Incorporating Banana Skin Powder and Palm Oil Fuel Ash Strengthened with Carbon Fibre Reinforced Plate
Authors: Mohamad Noridah , Afif Iman Muhammad , Aziz Abdul Samad Abdul , Othuman Mydin Md Azree , Jusoh Suriani , Sofia Anis , Aziz Khalidah , Lee Bryan
Published: September 2019

This paper investigated the chemical properties of banana skin powder (BSP) and palm oil fuel ash (POFA), and mechanical properties of lightweight foamed concrete (LFC) incorporating BSP and POFA strengthened with carbon fibre reinforce polymer (CFRP) plate. The BSP and POFA are added in the LFC mixture at various percentages as cement and sand replacement, respectively. LFC cubes incorporating BSP and POFA, LFC-BSP-POFA, were cast and tested under compression to determine its compressive strength. LFC-BSP-POFA prisms strengthened with 100 mm and 150 mm length of CFRP plates glued on its bottom mid-span surface were cast and tested under four point bending load to determine its flexure behaviour. From the chemical test, it was found that BSP and POFA each contain pozzolan materials, which are 55.98% and 51.83% silicon dioxide, and 2.71% and 2.32% aluminium oxide, respectively. From the mechanical property tests, compressive and flexural strength increased when percentage of BSP and POFA incorporated in the LFC increased. Meanwhile, CFRP plate managed to strengthen the LFC prism further where higher ultimate load recorded when longer CFRP plate was used.
Determining Changes in the Engagement of Screw Rotors Due to Transmission Error
Authors: Mustafin Timur , Yakupov Ruslan , Khamidullin Mansur , Alyaev Valery , Khisameev Ibragim
Published: September 2019

As a rule, the structural analysis of screw compressors during their design comes down to determining the geometric dimensions of the screws, the position of their window edges, as well as the gas forces acting on the compressor rotors. The latter determine the loads on the compressor bearings and affect vibration of the rotors and the compressor as a whole. Their effect plays the dominant role but not the only one. To create a mathematical model describing the vibration state of rotors, determining all additional forces acting on the compressor rotors that arise in the course of its operation under normal operating conditions is also required. These include the manufacturing inaccuracies causing skewing and bending of the rotor axles, as well as contact forces caused by the interaction of rotors due to their deviation from the nominal position. The latter are the least studied and, as a rule, are typical only for oil-flooded screw compressors with no rotor synchronisation mechanism. This article is devoted to the determination of rotor dynamics and the forces caused by rotor teeth engagement. In future, its results will serve as a basis for developing a rotor vibration state model. Meanwhile, the analysis of results obtained already at the current research stage allows to decrease their impact and effect.
CFD Modelling of Coupled Heat Transfer between Solid and Fluid in a Twin Screw Compressor
Authors: Ding Hui , Jiang Yu , Dhar Sujan
Published: September 2019

Temperature variation in a compressor is very critical for compression performance and efficiency. To accurately predict the thermal dynamic behaviour of a compressor, heat transfer between metal components and the working fluid needs to be properly evaluated in CFD simulation. Thermal expansion of solid components due to temperature increase may also cause excessive abrasion of metal parts and changing in leakage clearance. Solving conjugate heat transfer (CHT) of twin screw compressors not only needs to deal with complex moving rotor geometry, but also needs to consider huge difference of temperature propagation time scale inside different media. Typically, heat propagation is much slower in solid than in compressed gas. Therefore, it may take many compressor revolutions to reach a stable CHT solution if heat conduction inside solid and thermodynamic temperature change of compressed gas are directly coupled in a CFD simulation. The run time of simulation may become impractical.

In this paper, an innovative approach solving conjugate heat transfer using the Mixed Timescale Coupling method between different media will be described in detail. This approach can address time scale difference in heat propagation. The proposed approach will be applied to a twin screw compressor. Simulation results will be compared with available test data. Effects of conjugate heat transfer will be evaluated by comparing the simulation results for the cases with and without considering conjugate heat transfer. Thermal expansion of the solid rotor will also be evaluated using predicted temperature distribution. Simulation will also demonstrate that the approaches used in the paper are robust, fast, and user friendly, and can be readily applied to industrial compressor systems.
Use of CFD to Investigate Flow Characteristics and Oil Distribution Inside an Oil-injected Screw Compressor
Authors: Zhang J W , Wu Y R , Hsieh S H , Huang C S
Published: September 2019

The well-developed CAE tools are used to investigate flow characteristics and oil distribution inside an oil-injected screw compressor. The flow field of gas mixed with oil is calculated by ANSYS CFX. TwinMesh generates high quality hexahedral grids for the compression chambers. There are two cases studied in this study. In the first case, the compressor models under four loading conditions are analyzed. The pressure curve is used to see if the designed built-in volume index is appropriate. In the second case, the compressor models under oil-free and oil-injected conditions are analyzed. The pressure gradients on rotor surfaces and velocity vector fields are used to describe the effects of lubrication and sealing in the sealing line gap, the tip gap, and the outlet end gap of rotors. The designer could optimize the slider and know if the oil is properly distributed in each gap.
An experimental investigation on pulsation & noise reduction by shunt pulsation trap with a nozzle for compressors operating in under-compression
Authors: Huang P X , Yonkers S
Published: September 2019

This paper is a continuing work from the same authors on the same topic on gas pulsation and noise control using a shunt pulsation trap (SPT) method by Huang [1, 2, 3]. Traditionally, a serial pulsation dampener/muffler, often a reactive type, is connected AFTER the discharge of a positive displacement compressor. It has been demonstrated in the previous experimental investigations that gas pulsations from under-compression (UC) can be as effectively controlled by an alternative scheme - shunt pulsation trap (SPT), which is more compact and tackles the gas pulsations BEFORE the compressor discharge. Two dampening SPT schemes were investigated and compared: using a perforated plate (p-plate) vs. a perforated tube (p-tube). However, the pulsation induced noise is still a challenge with SPT employment alone. The focus of the present paper investigates experimentally the effect of a new dampening scheme - combining a SPT with a nozzle and an integrated absorptive silencer (IAS) to undertake both pulsation and noise problems at source. It is found that an ASME nozzle SPT with IAS scheme has superior noise reduction capability than both the p-tube + IAS scheme and the traditional scheme using premium silencers. Furthermore, the addition of an integrated absorption silencer (IAS) is not suffering as much back pressure drop associated with traditional reaction type silencers and therefore will not affect system efficiency. The integration of absorptive silencer into a nozzle or p-tube based SPT would provide an optimal design choice for size/weight and pulsation/noise reduction and potentials for energy saving for PD compressors operating in UC mode.
Vapor Compression Cycles for High Component Heat Loads on Next-Generation Small Satellites
Authors: Brendel Leon P M , Hengeveld Derek , Braun James E , Groll Eckhard A
Published: September 2019

High-power small satellites (SmallSats) have the potential to provide new and advanced capabilities; however, significant challenges prevent wide-spread use. Of these challenges, thermal management of high heat loads is most significant. This paper evaluates vapor compression cycles (VCCs) as a thermal management solution to increase the maximum component heat load at a fixed radiator area. The VCC with radiative heat transfer as a heat sink is described with analytical equations that couple the required compressor work input for a desired additional component heat load for a given second law efficiency. A figure of merit is defined. In a case study, the results of the equations are compared to a numerically modelled vapor compression cycle. Challenges for a realization of vapor compression cooling on-board SmallSats are pointed out.
Developing teamwork skills for students trained in compressors and refrigeration programs
Authors: Fedorova M A , Prokudina N A , Fedoseeva N Yu , Evdokimov  , Kapelukhovskaya A A , Yusha V L
Published: September 2019

While implementing the bachelor’s program in the fields of compressors and refrigeration, modern educational standards provide for the teamwork competence developing. The purpose of this study is to propose a system of developing this competence for students of the Petrochemical Institute, Omsk State Technical University. The main idea of the research is the application of an integrated interdisciplinary approach to all the competences of the graduate, involving various forms and methods of implementing the system of training highly skilled engineers. The team-building competence is formed both during instruction time and extracurricular time: in research, internships, sport and other activities. In addition, the work experimentally revealed that the competence under consideration is consistent with both the requirements of employers and the need for students self-realization while studying at a university. The article presents particular examples of this competence development in the course of basic professional subjects, as well as of Foreign language and Physical education. In particular, the Foreign language course was extended for the students of the mentioned training programs in comparison with other students. As for physical education, team skills are formed in the classroom and through the students participation in various sport competitions. Besides, the article describes the results of students participation in the program “Young professionals of Russia”, WSR. In addition, the interdisciplinary Petrochemical Institute project of the summer school for the first-year undergraduates, fully implementing the principles of complexity and consistency, is presented in the paper.
Vaneless diffusers characteristics simulating by means of neural networks
Authors: Nikiforov A , Avramenko D , Kuchumov A , Terentev S , Galerkin Yu , Solovyeva O
Published: September 2019

The paper presents the results of simulation of loss coefficient and the angle of flow at the outlet of diffuser in centrifugal compressor vaneless diffusers. The calculation was performed in a wide range of design and gas-dynamic parameters by means of neural networks. Also, an analysis performed by CFD (Computational Fluid Dynamics) methods is presented. In order to obtain mathematical models, a data sampling was used for vaneless diffusers with the following characteristics: relative width is b
2 / D
2 = 0.014 – 0.1, outlet relative diameter is D4 / D2 = 1.4 – 2.0, inlet flow angle is 2 α2 = 10 – 90 º, velocity coefficient is λ
c2 = 0.39 – 0.82, Reynolds numbers corresponding to them are Re
b2
= 87 500 - 1 030 000.

In order to improve the accuracy of simulating using neural networks, various recommendations on the preparation and processing of initial data were collected and tested: identification of conflict samples and outliers, data normalization, improving the quality of the neural networks training under the insufficient amount of sampling, etc. Application of the listed recommendations and an essential expansion of mathematical models definition significantly improved the accuracy of simulating.

A simulation experiment based on neural models for studying the influence of dimensions, diffuser shape, and similarity criteria made it possible to check the physical adequacy of mathematical models, to obtain new data on energy conversion processes and to establish a number of recommendations on the optimal design of vaneless diffusers.
Optimization of geometry blade for modern high pressure compressor
Authors: Marchukov E , Egorov I , Kretinin G , Karonic B , Fedechkin K.
Published: September 2019

An integration of CFD-3D codes and modern efficient methods of optimization is essential for the contemporary compressors improvement. In order to solve optimization tasks the insular information exchange circle was created. The data circulates between the mathematical model of the stream in a compressor, the algorithm of compressor’s geometry construction based on parameterization and algorithm of optimization itself. The mathematical model of the compressor covers procedures of mesh generation and calculations using CFD code. This model has been verified by experimental data.

A high-pressure compressor of multi regime gas turbine engine for supersonic civil aircraft has been considered as the object of our study. The goal of the research was to increase the efficiency in the design point with the ensured preset gas dynamic parameters under other modes. The variables for optimization task were installation angles and the shape of the middle line of the profile in three sections along the height of the compressor rotor and stator blades. The total amount of independent variables was 72. As a result of the study the optimal geometry for the stator and rotor blades in supersonic aircraft engine has been obtained. The initial project efficiency had been improved by 1-2%, while stability margin remained constant.
Detailed prediction of fluid-solid coupled phenomena of turbulent flow through reed valves
Authors: González I , Naseri A , Rigola J , Pérez-Segarra C D , Oliva A
Published: September 2019

The operation of self-actuated valves in suction and discharge processes plays a crucial role in the thermal efficiency and structural reliability of hermetic reciprocating compressors. The present work provides a thorough description of an in-house numerical method based on a partitioned fluid-structure interaction algorithm intended to obtain high-fidelity numerical predictions and optimise valve system design. A large eddy simulation model is used for the turbulent flow, whereas a normal mode superposition assumption along with an impact penalty method is used for the reed. Under this framework, a detailed analysis of the coupled problem with a straight and tapered exit ports is carried out. Differences in effective flow area and pressure drop are found as a result of the port geometry, but also of the valve velocity.
Development of Augmented Reality Applications for the Entire Spectrum of Screw Compressor Manufacturing Process
Authors: Milligan W J , Gillan S M , Harrison D K
Published: September 2019

Augmented Reality (AR) in industrial applications connects users across digital and physical worlds and coupled with rapid return of investment, easy adoption, and as a meaningful way to stand out from the competition, AR is quickly becoming increasingly common in the industrial world. This paper first provides the reader with a description on what exactly is augmented reality and the difference between augmented reality and virtual reality, before moving onto describing the scope of this new application for an organisation like Howden. A brief analysis of how augmented reality is quickly finding a footing within this sphere is offered alongside an overview of the main players and actors. The paper then focuses on how the 3D CAD modelling already completed by the research and development, bare-shaft engineering and package engineering teams can be utilised in the rapid development of augmented reality applications. Examples of how Howden are developing and using these AR applications are then given with specific reference to the Screw sales teams using them to show prospective clients the model of their package / machine; the Screw package build teams sharing knowledge using AR during package fit-out and hazard and operability studies; the bare-shaft test team using AR within their acoustic enclosure and finally the impact of AR in the service teams. The paper concludes with how, as this technology becomes more mainstream, manufacturers adopting AR can significantly add value to their customers experience both in terms of service and satisfaction but also differentiate themselves from their competitors.
Dietary supplementation with garcinol during late gestation and lactation facilitates acid–base balance and improves the performance of sows and newborn piglets1
Authors: Wang Tongxin , Yao Weilei , Xia Jun , Li Juan , Shao Yafei , Huang Feiruo
Published: September 2019

The present study was conducted to evaluate the effects of dietary garcinol supplementation during late gestation (from the 90th day of pregnancy; day 90) and lactation on the acid–base balance of the umbilical cord blood and performance of sows and piglets. Sixty sows (Duroc × Yorkshire × Landrace; second- or third-parity; n = 20) were randomly divided into 3 gestation (day 90 of pregnancy) or lactation treatments, control diet (CON; basal diet), basal diet with 200 mg garcinol, and basal diet with 600 mg garcinol per kg of feed. The body weight (BW); backfat thickness and litter size of the sows; and birth weight, weaning weight, and mortality of piglets were recorded. Sows’ blood and piglets’ umbilical cord blood were collected for the measurements of hematological parameters and antioxidative and immune indexes, and acid–base balance parameters, respectively. The colostrum and milk and fecal samples of the sows were also collected for analysis of milk composition and apparent total tract nutrient digestibility. Garcinol had no effect on the BW and backfat thickness of the sows but significantly increased the birth weight and weaning weight of piglets (P < 0.05) and decreased the mortality (P < 0.05). Moreover, the white blood cell counts and neutrophil count, mean cell hemoglobin, superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in the plasma of the sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group, whereas the malondialdehyde (MDA) content was decreased (P < 0.05). The garcinol treatment significantly increased the pH, HCO3− and base excess values (P < 0.05), whereas it decreased the pCO2 and lactate content (P < 0.05) in the umbilical blood. Dry matter (DM), ash, and ether extract in the colostrum were similar between groups (P > 0.05), whereas the garcinol significantly increased the crude protein (CP) in the milk. In addition, the content of immunoglobulin A (IgA) and immunoglobulin G (IgG) in the plasma of piglets and in colostrum and milk of sows were increased more significantly (P < 0.05) in the garcinol groups than that in the CON group. The apparent total tract nutrient digestibility was similar between treatments. Collectively, this study indicates that sows fed with garcinol in late gestation and lactation showed improved maternal health and antioxidative status, milk protein content, acid–base balance in the umbilical cord blood, and growth performance in piglets, showing promise in natural plant extract nutrition for sows.
Draft Assembly ofPhytophthora capsicifrom Long-Read Sequencing Uncovers Complexity
Authors: Cui Chenming , Herlihy John H. , Bombarely Aureliano , McDowell John M. , Haak David C.
Published: September 2019

Resolving complex plant pathogen genomes is important for identifying the genomic shifts associated with rapid adaptation to selective agents such as hosts and fungicides, yet assembling these genomes remains challenging and expensive. Phytophthora capsici is an important, globally distributed plant pathogen that exhibits widespread fungicide resistance and a broad host range. As with other pathogenic oomycetes, P. capsici has a complex life history and a complex genome. Here, we leverage Oxford Nanopore Technologies and existing short-read resources to rapidly generate a low-cost, improved assembly. We generated 10 Gbp from a single MinION flow cell resulting in >1.25 million reads with an N50of 13 kb. The resulting assembly is 95.2 Mbp in 424 scaffolds with an N50length of 313 kb. This assembly is approximately 30 Mbp bigger than the current reference genome of 64 Mbp. We confirmed this larger genome size using flow cytometry, with an estimated size of 110 Mbp. BUSCO analysis identified 97.4% complete orthologs (19.2% duplicated). Evolutionary analysis supports a recent whole-genome duplication in this group. Our work provides a blueprint for rapidly integrating benchtop long-read sequencing with existing short-read data, to dramatically improve assembly quality and integrity of complex genomes and offer novel insights into pathogen genome function and evolution.
Lung, spleen and oesophagus tissue remains stable for scRNAseq in cold preservation
Authors: Madissoon E. , Wilbrey-Clark A. , Miragaia R.J. , Saeb-Parsy K. , Mahbubani K. , Georgakopoulos N. , Harding P. , Polanski K. , Nowicki-Osuch K. , Fitzgerald R.C. , Loudon K.W. , Ferdinand J.R. , Clatworthy M.R , Tsingene A. , Van Dongen S. , Dabrowska M. , Patel M. , Stubbington M.J.T. , Teichmann S. , Stegle O. , Meyer K.B.
Published: September 2019

Background

The Human Cell Atlas is a large international collaborative effort to map all cell types of the human body. Single cell RNA sequencing can generate high quality data for the delivery of such an atlas. However, delays between fresh sample collection and processing may lead to poor data and difficulties in experimental design. Despite this, there has not yet been a systematic assessment of the effect of cold storage time on the quality of scRNAseq

Results

This study assessed the effect of cold storage on fresh healthy spleen, oesophagus and lung from ≥5 donors over 72 hours. We collected 240,000 high quality single cell transcriptomes with detailed cell type annotations and whole genome sequences of donors, enabling future eQTL studies. Our data provide a valuable resource for the study of these three organs and will allow cross-organ comparison of cell types.

We see little effect of cold ischaemic time on cell viability, yield, total number of reads per cell and other quality control metrics in any of the tissues within the first 24 hours. However, we observed higher percentage of mitochondrial reads, indicative of cellular stress, and increased contamination by background “ambient RNA” reads in the 72h samples in spleen, which is cell type specific.

Conclusions

In conclusion, we present robust protocols for tissue preservation for up to 24 hours prior to scRNAseq analysis. This greatly facilitates the logistics of sample collection for Human Cell Atlas or clinical studies since it increases the time frames for sample processing.
Visual acuity performance level is independent of locomotion
Authors: Swain Alex D. , Park Eunsol , Cheng Zhang Yu , Kowalewski Nina , Sun Angela , Allen Tessa , Kuhlman Sandra J.
Published: September 2019

Locomotion has a global impact on circuit function throughout the cortex, including regulation of spatiotemporal dynamics in primary visual cortex (V1). The mechanisms driving state-changes in V1 result in a 2-3 fold gain of responsiveness to visual stimuli. To determine whether locomotion-mediated increases in response gain improve the perception of spatial acuity we developed a head-fixed task in which mice were free to run or sit still during acuity testing. Spatial acuity, ranging from 0.1 to 0.7 cycles/°, was assessed before and after 3-4 weeks of reward-based training in adult mice. Training on vertical orientations once a day improved the average performance across mice by 22.5 ± 0.05%. Improvement transferred to non-trained orientations presented at 45°, indicating that the improvement in acuity generalized. Furthermore we designed a second closed-loop task in which acuity threshold could be directly assessed in a single session. Using this design, we established that acuity threshold matched the upper limit of the trained spatial frequency; in two mice spatial acuity threshold reached as high as 1.5 cycles/°. During the 3-4 weeks of training we collected a sufficient number of stimulus trials in which mice performed above chance but below 100% accuracy. Using this subset of stimulus trials, we found that perceptual acuity was not enhanced on trials in which mice were running compared to trials in which mice were still. Our results demonstrate that perception of spatial acuity is not improved by locomotion.
Dysfunctional and compensatory brain networks underlying math fluency
Authors: La Michelle AN , Saha Debjani , Berman Karen F , Tan Hao Yang
Published: September 2019

Poor math fluency, or timed calculation (TC) performance, is a characteristic of dyscalculia, a common cause of poor educational and occupational outcomes. Here, we examined neural substrates of dysfunctional math fluency and potential compensatory mechanisms. We performed functional MRI scans of participants with divergent performance on an event-related TC paradigm (poor TC, <0.5 accuracy, n=34; vs. controls, accuracy>0.8, n=34). Individuals with poor TC had decreased intraparietal sulcus (IPS) engagement, and decreased IPS-striatal and IPS-prefrontal effective connectivity. We next examined an independent well-performing sample (TC accuracy>0.8, n=100), stratified according to relatively low-versus high-IPS activation during TC. Relatively reduced IPS engagement, or patterns of IPS-related effective connectivity similar to those with poor TC, appeared to be compensated for by increased engagement of effective connectivity involving fusiform gyrus, angular gyrus, inferior frontal gyrus and striatum. Neural connectivity involving high-level visual processing in fusiform gyrus and related ventral cortical networks may be relevant in compensatory function ameliorating aspects of dyscalculia and mathematical difficulty.