bluuebunny/crossref_metadata_2025 huggingface dataset:
Enantioselective synthesis of (R)-2-cubylglycine including unprecedented rhodium mediated C–H insertion of cubane
Authors: Houston Sevan D. , Chalmers Benjamin A. , Savage G. Paul , Williams Craig M.
Published: January 2019

An enantioselective synthesis of the non-proteinogenic amino acid (R)-2-cubylglycine and the first examples of cubane C–H insertion are reported.
Combined atomic force microscopy (AFM) and traction force microscopy (TFM) reveals a correlation between viscoelastic material properties and contractile prestress of living cells
Authors: Schierbaum Nicolas , Rheinlaender Johannes , Schäffer Tilman E.
Published: January 2019

Combined AFM with TFM is a powerful tool to simultaneously and directly measure “passive” viscoelastic material properties and “active” contractile prestress of living cells at the nanoscale.
Hollow mesoporous hetero-ZnO/ZnMnO3 microspheres: template-free formation process and enhanced lithium storage capability towards Li-ion batteries as a competitive anode
Authors: Zhang Yanru , Wang Zhengluo , Zaman Fakhr uz , Zhao Zhiwei , Sun Xuan , Zhang Jinyang , Hou Linrui , Yuan Changzhou
Published: January 2019

Hierarchical hollow mesoporous ZnO/ZnMnO3 microspheres were fabricated and exhibited outstanding Li-storage behaviors as competitive anode for Li-ion batteries.
Structure and mechanism of the ESCRT pathway AAA+ ATPase Vps4
Authors: Han Han , Hill Christopher P.
Published: January 2019

The progression of ESCRT (Endosomal Sorting Complexes Required for Transport) pathways, which mediate numerous cellular membrane fission events, is driven by the enzyme Vps4. Understanding of Vps4 mechanism is, therefore, of fundamental importance in its own right and, moreover, it is highly relevant to the understanding of many related AAA+ ATPases that function in multiple facets of cell biology. Vps4 unfolds its ESCRT-III protein substrates by translocating them through its central hexameric pore, thereby driving membrane fission and recycling of ESCRT-III subunits. This mini-review focuses on recent advances in Vps4 structure and mechanism, including ideas about how Vps4 translocates and unfolds ESCRT-III subunits. Related AAA+ ATPases that share structural features with Vps4 and likely utilize an equivalent mechanism are also discussed.
Local ZigZag Max histograms of pooling pattern for texture classification
Authors: Roy Swalpa Kumar , Dubey Shiv Ram , Chaudhuri Bidyut B.
Published: January 2019

The efficiency of any texture classification model confides on descriptor used for similarity matching. The formation of image descriptor is a challenging and important task in computer vision. This Letter introduces a local ZigZag Max histograms of pooling pattern (LZMHPP) for classification of texture images. To compute the descriptor, first the dissimilarity between centre pixel and its neighbours is computed for each image patch over the whole image, then the dissimilarity map is encoded with different type of ZigZag ordering mechanism, and finally the Max histograms pooling is used to form LZMHPP descriptor from two complementary ZigZag weighted structures and achieves sufficient robustness under geometric variations. The experimental study on KTH‐TIPS and CUReT texture databases indicates the efficiency and supremacy of LZMHPP descriptor for texture classification.
Interplane cross‐saturation in multiphase machines
Authors: Jecmenica Milos , Brkovic Bogdan , Levi Emil , Lazarevic Zoran
Published: January 2019

The use of electrical machines in electric vehicles and high‐power drives frequently requires multiphase machines and multiphase inverters. While appropriate mathematical models under the linear magnetic conditions are readily available for multiphase machines, the same cannot be said for the models of the saturated multiphase machines. This study examines the saturation in an asymmetrical six‐phase induction machine under different supply conditions and addresses the applicability of the existing saturated three‐phase machine models for the representation of saturated multiphase machines. Specifically, the mutual coupling between different sequence planes in the vector space decomposed model under saturated conditions is analysed. The study relies on analytical considerations, finite element analysis and experimental results. It is shown that the saturation of the main flux path is influenced by the current components in the orthogonal (non‐fundamental) sequence plane. This implies the need to develop new multiphase machine models which take this effect into account.
Ultra‐wideband high‐gain dipole antenna evolved from hexagonal Sierpinski grid fractal gasket
Authors: Li Daotie , Wu Zhonglin , Mao Jun‐Fa
Published: January 2019

Ultra‐wideband high‐gain dipole antennas are urgently desired for mobile communications. A novel fractal‐evolved dipole called modified hexagonal Sierpinski grid carpet dipole, of which size is about 1.5λ in upper band is developed. With self‐similarity and periodicity of fractal geometry, the dipole antenna is excellent in performances. It has an ultra‐wide bandwidth and high gain, due to a so‐called ‘array effect of element antenna’. It presents a gain as high as 12.7 dBi and stable unidirectional radiation patterns within band of 2.0–3.93 GHz (BW = 65.1%). In addition, the dipole also has good cross‐polarisation differentiation, high efficiency, high front‐to‐back‐ratio, small size, low‐profile (0.156λL), and light weight. A prototype was fabricated from a plastic body by 3D printing technology and then electroplated on the surface. Then, the sample was measured and compared with simulation results, and good agreements are obtained between them. So, correctness and validity of the design methodology are verified successfully. Due to these remarkable advantages, the fractal antenna is attractive to many radio services, such as mobile communications, defence and military, public security, aeronautics and aerospace, and so on.
New dual H‐bridge converter for continuous space vector modulation
Authors: Durán Tomás , Neira Sebastián , Pereda Javier , Rojas Felix
Published: January 2019

Multilevel converters are a significant improvement in the DC–AC conversion technology, reaching higher power quality in medium‐voltage applications and using standard semiconductors in a smarter way than conventional converters, without necessarily increasing the cost. However, multilevel technology remains discrete and its only way to reduce the overall total harmonic distortion leads on the generation of several discrete levels on the output voltage. Therefore, it is not possible to reduce the harmonic distortion to negligible values, unless a big number of semiconductors are used, which is not cost‐effective for low‐voltage applications, limiting the reliability of the system. This study proposes a new dual H‐bridge inverter that generates a three‐phase output voltage with negligible distortion using two variable DC–DC power sources and a new continuous space vector modulation. Simulation and experimental results show high‐quality output voltages. The topology is simple and uses only 12 semiconductors, but it requires special attention in the variable DC voltage converters, which can limit the maximum output frequency. Therefore, the solution is suitable for low power applications that require high power quality using small filters or none filters at the AC side. The results were obtained and validated using an experimental laboratory prototype under different operating conditions.
Study on pollution flashover characteristic of insulators on 500 kV AC transmission lines in high‐altitude area
Authors: Huang Ruiping , Zhou Jun , Xu Yueneng
Published: January 2019

Pollution flashover performance of insulators is one of the key factors to be considered in the selection of external insulation for transmission lines at high‐altitude areas. In pollution laboratories at Tibet high‐altitude test base and Beijing ultra high voltage direct current (UHVDC) test base, artificial pollution tests of insulators adopted in AC 500 kV transmission project are performed both in sea‐level region and real high‐altitude regions, through which flashover voltages at typical equivalent salt deposit density are obtained. The relationship between altitude and flashover voltage is acquired as well.
Chance constrained dynamic optimisation method for AGC units dispatch considering uncertainties of the offshore wind farm
Authors: Zhao Xia , Ye Xiaobin , Yang Lun , Zhang Rongrong , Yan Wei
Published: January 2019

The continuing growth of an offshore wind farm integrated into a power grid via high‐voltage DC has posed great challenges for automatic generation control (AGC) of the power system. To address these challenges, a new concept of ‘dynamic dispatch of AGC units (DDA)’ under control performance standards from the view of economic dispatch (ED) has been proposed in the previous work, and proved to be an effective technique to co‐operate the AGC units with different ramping rates and to fill the gap between ED and AGC. However, the existing DDA model is deterministic in nature, which can hardly deal with the uncertain forecasting error of the offshore wind power output. A novel stochastic DDA model based on chance‐constrained programming is proposed considering a random offshore wind power forecasting error, and a hybrid algorithm combining the evolutionary programming algorithm and point estimate method is then developed to solve the stochastic model. Numerical results from a two‐area test system with additional offshore wind power generation demonstrate the accuracy and computation efficiency of the hybrid algorithm and the benefits offered by the stochastic AGC dispatch method.
Control of the Grushin equation: non-rectangular control region and minimal time
Authors: Duprez Michel , Koenig Armand
Published: January 2019

This paper is devoted to the study of the internal null-controllability of the Grushin equation. We determine the minimal time of controllability for a large class of non-rectangular control regions. We establish the positive result thanks to the fictitious control method and the negative one by interpreting the associated observability inequality as an L2 estimate on complex polynomials.
Tsunami hazard mapping and loss estimation using geographic information system in Drini Beach, Gunungkidul Coastal Area, Yogyakarta, Indonesia
Authors: Marfai Muh Aris , Sunarto  , Khakim Nurul , Fatchurohman Hendy , Cahyadi Ahmad , Wibowo Yunus Aris , Rosaji Fredi Satya Candra
Published: January 2019

The southern coastal area of Java Island is one of the nine seismic gaps that prone to tsunamis. The entire coastline in one of the regencies, Gunungkidul, is exposed to the subduction zone in the Indian Ocean. Also, the growing tourism industries in the regency increase its vulnerability, which places most of its areas at high risk of tsunamis. This conditions are expected to increase the tsunami risk and loss potential alongside the coastal area. This research aims to model tsunami inundation and estimate the loss that caused by tsunami. Detailed DEM generated from UAV photogrammetry. Based on the model, several inundation scenario. Based on the model, the 4-m inundation did not affect a wide area. The modelling proves that the extent of tsunami-inundated areas is directly proportional to the wave height of tsunamis. The inundated area extend as the inundation scenario increase. Hilly karst topography prevent the water to inundate wider areas. The loss calculation shows that the material loss at the trading centre was relatively much higher than the other land uses because its included not only the value of the building but also the commodities and the strategic importance of their market.
Plantain Herb Extracts significantly attenuate the quorum sensing-controlled virulence factors and inhibit biofilm formation in Pseudomonas aeruginosa PAO1
Authors: Li Shan , Yao Jiangning , Li Haoming
Published: January 2019

Pseudomonas aeruginosa is a Gram-negative organism that can survive under harsh conditions, and it is also an opportunistic pathogen that can produce cell-associated extracellular virulence factors. Several of these virulence factors have been demonstrated to be regulated by quorum sensing (QS). Plantain Herb has been used as antibacterial agents for many centuries in China. In this study, we analyzed Plantain Herb Extracts (PHE) at the concentration of 16 μg/mL (Group A, MIC), 8 μg/mL (Group B, 1/2 MIC) and 4 μg/mL (Group C, 1/4 MIC) for inhibition of the virulence factors production and biofilm formation in P. aeruginosa PAO1. The virulence factors included pyocyanin, rhamnolipids, protease and alginate. PHE showed significant inhibition of virulence factors as compared to the control group without interfering its growth. Thus, PHE might be a potent QS inhibitor and anti-biofilm agent in the treatment of Pseudomonas aeruginosa infections.
Research Progresses of the Mechanism of Insulin Resistance in Type II Diabetes
Authors: Liu Xinming
Published: January 2019

Insulin resistance(IR) is the most primary pathological mechanism of type II diabetes, a metabolic disorder characterized by chronic hyperglycemia. Insulin transduction pathways have significant effects on IR, and they are mainly classified into two pathways: insulin receptor substrate-1 (IRS- 1)/phosphatidyl inositol 3 kinase (PI3K)/protein kinase (PKB) pathway and Ras/Raf/mitogen-activated protein kinase (MAPK) pathway. Resulted from various reasons such as obesity, oxidative stress and endoplasmic reticulum(ER) stress, if any site in the pathway is abnormal, IR will be caused. Therapies to IR is to enhance insulin sensitization, including adiponectin, endolipid and metformin. We review the mechanisms of IR in type II diabetes.
Studies on Ejection of Cell Culture Medium by Electrohydrodynamic Method
Authors: Haiyi Zhang , Can Wang , Fei Wang , Yiwei Wang , Zhihai Wang , Xi Chen , Jingang Gui
Published: January 2019

Sample deposition based on micro-droplet ejection has broad application prospects in the field of biomedicine. Ejection of RPMI-1640 medium (without and with cells) is investigated experimentally using a home-build electrohydrodynamic (EHD) ejection system, consisting of a liquid supplier and a nozzle, a high voltage source, a droplet collector, and a high speed photography module. Electric voltage is applied between the nozzle and the droplet collector. The liquid surface is charged and the ejection takes place when electric force overcomes the surface tension. The ejection process is studied by using high speed photography and image processing. At low voltage, a uniform ejection state is established with ejection frequency typically less than 50Hertz. At sufficiently high voltage, another uniform ejection state is reached with ejection frequency as high as 1300Hz. Human peripheral blood mononuclear cells, after ejection, show survival rates higher than 79%, manifesting EHD ejection as a promising technique for cell printing.
Optimization of Cephalosporin C Acylase Immobilization
Authors: Tong Shuangming , Zhu Linlin , Wang Xiaona , LI Xi , Chang Yanhong , Luo Hui
Published: January 2019

Cephalosporin C Acylase (CCA), the key biocatalyst in one-step enzymatic production of 7- amino cephalosporanic acid (7-ACA), was immobilized by amino-activated carrier (LX-1000HA) and epoxy-activated carriers (ES-103B, LX-1000EPC), and the activity was assayed. ES-103B carriers showed an advantage than the others. The amount of free enzyme and salt concentration were tested, and the optimum conditions were 1400U/g and 0.9M. In addition, two different methods (by shaker and packed column) were used in CCA immobilization, and the results demonstrated that the former obtained a higher immobilized CCA activity.
Effects of Grinding Methods on Physicochemical Properties of Crude Polysaccharides from Phellinus baumii
Authors: Li Tingting , Yang Yan , Chen Linjun , Yang Wanling
Published: January 2019

The physicochemical properties of Phellinus baumii polysaccharides extracted from the fruiting bodies by different grinding methods were studied in this paper. Compared with ordinary grinding methods, superfine grinding technology exerts significantly higher yields of crude polysaccharides, polysaccharide contents and β-Glucan contents of six samples. HPSEC-MALLS- RI analysis shows the molecular weight distribution of P.baummii crude polysaccharides, which indicates superfine grinding technique generates higher molecular weight fractions and larger polydispersities. The 6 kinds of crude polysaccharides have obvious effects on NO generation of RAW264.7 cells, which indicated that crude polysaccharides from P.baumii may have some immune-enhancing effects. Meanwhile, CW30 and FP30 show the best immune enhancing effects. However, CW50 and CW70 exert weaker immune-enhancing effects compared with FP50 and FP70.
Forming pressure effect on microstructure and mechanical properties of nanocrystalline aluminum synthesized by inert gas condensation
Authors: Wu Shangshu , Yu Zhou , Wang Junjie , Zhang Hanxin , Pei Chaoqun , Fu Shu , Fu Hao , Meng Jiajie , Feng Tao
Published: January 2019

The preparation of nanocrystalline aluminum (NC Al) was conducted in two steps. After the NC Al powder was synthesized by an Inert gas condensation (IGC) method in a helium atmosphere of 500 Pa, the NC Al powder was in-situ compacted into a pellet with a 10 mm diameter and 250 μm-300 μm thickness in a high vacuum (10-6Pa-10-7Pa) at room temperature. The NC Al samples were not exposed to air during the entire process. After the pressure reached 6 GPa, the relative density could reach 99.83%. The results showed that the grain size decreased with the increased of in-situ forming pressure. The NC Al samples present obvious ductile fracture, and the tensile properties were greatly changed with the increase of forming pressure.
Study on interface characteristics and frost resistance of recycled concrete
Authors: Liu Ying , Peng Peng
Published: January 2019

The structural characteristics of recycled aggregate concrete and its damage mechanism have been analyzed in this paper. The recycled aggregate has been classified into three types through particle shaping and then frost resistance property of recycled concrete with different cement volume has been analyzed through the test. According to the test results, frost resistance property of the recycled concrete is C >B >A, therefore, particle shaping can obviously improve quality and durability of the recycled coarse aggregate.
Spatial cluster and Heterogeneity Research on Energy-Related Carbon Emissions in Districts and Counties of Guangdong Province
Authors: Wang Wenxiu , Ke Shangjun , Zhao Daiqing , Cai Guotian
Published: January 2019

Energy-related carbon emissions in districts and counties of Guangdong province from 2005 to 2016 are researched based on spatial econometrics method in this article, and significance cluster area and heterogeneity area are precise pinpointed. Conclusions are as follows: (1) total carbon emissions and per capita carbon emissions exist significance global spatial autocorrelation in the year 2005-2016, and formed significance high-high cluster area in districts and counties of Guangzhou city, Shenzhen city and Dongguan city. It also formed three significance low-low cluster areas in districts and counties of eastern, western and northern of Guangdong province. Low-high heterogeneity area and high -low heterogeneity area often appears in the scope of high-high cluster area and low-low cluster area. (2)Carbon emission intensity not exist significance global spatial autocorrelation, but exist significance cluster area and heterogeneity area in the ecological development areas of eastern, western and northern of Guangdong province. In the end, the paper puts forward the regional and detailed policy recommendations for efficient carbon emission reduction for each cluster type region: carbon high-high cluster areas are priority reduce emissions area, heighten energy saving technology and optimize industrial structure are two grippers to reduce emissions. Low - low carbon emissions concentrated area in western of Guangdong should primarily develop high and new technology industry. Low low carbon emissions concentrated areas and high - high carbon emissions intensity concentrated area for eastern and northern of Guangdong province should try hard to wins ecological compensation at the same time focus on developing ecological tourism.
The main geothermal reservoirs in the south Algeria and their interest for local economic development
Authors: Ait-Ouali Abdelkader , Ouali Salima , Hadjiat MM , Imessad Khaled
Published: January 2019

The study area is one of the important geothermal provinces in south Algeria. It is characterized by a hot arid climate with intense dryness and very high evaporation rates. The Albian geothermal system is exploited by the wells mainly for domestic and agricultural purposes. The sandstone Continental Intercalary (CI) formation constitutes the reservoir for the Albian aquifer, covering an area of 600,000 km2. This reservoir is covered by calcareous formations which yield the chemical characteristics of highly mineralized Na-Cl type representing the deep thermal waters and Ca-SO4 type determined the presence of evaporate lithology . For a better understanding of geothermal reservoir characteristic, a multidisciplinary approach was adopted, including hydrogeochemistry and geothermometry. More than fifty samples collected from wells recently in 2017 with a temperature average between 38 and 60° C and conductivities range from 2010 to 3460 μS/cm. Geochemical analysis of those thermal waters exhibits a certain degree of salinity with sodium-chloride type waters domination. The maximal geothermal reservoir temperature estimated using geothermometry is about 120°C.
Development of a footstep power generator in converting kinetic energy to electricity
Authors: Ang Chun Kit , Al-Talib Ammar A. , Tai Sook Meng , Lim Wei Hong
Published: January 2019

Kinetic energy is considered as one of the renewable energies. Substantial amounts of researches were conducted to investigate the feasibility of converting the kinetic energy into electricity. Nevertheless, most of these previous works emphasized on the selection of suitable materials and the design of power generator which tends to be complicated. In this paper, a simple and yet low cost mechanism has been proposed to enhance the performance and efficiency of energy conversion from kinetic energy to electricity energy by placing a mechanical footstep power generator on the hind foot region. A total of 45 individuals were invited to participate in the experiments and the experiment results are then compared with the theoretical results.
Assessment of geochemical barriers at preservation of low-level radioactive waste storages
Authors: Boguslavsky Anatoly , Gaskova Olga , Naymushina Olga
Published: January 2019

The work considers geochemical aspects of the natural and man-made system for storing radioactive waste (RW) from one of the Siberian enterprises of the fuel and nuclear cycle. Careful geochemical testing of key sites of the system allows us to identify geochemical barriers that prevent the spread of uranium outside the sludge storage. In addition, experiments were conducted on the leaching of the sludge material in the laboratory using modern methods for determining the composition of solutions and solid phases, as well as experiments on uranium sorption on the main types of subsoil. Experimental and thermodynamic modeling of uranium deposition processes confirms that the system studied satisfactorily copes with the absorption of uranium taken out of the sludge storage due to dilution and sorption on rocks and bottom sediments. Particularly favorable are bottom sediments rich in organic matter, which bind uranium to organic-mineral complexes.
Studying molecular profiles above the Cherenkov Telescope Array sites
Authors: Munar-Adrover Pere , Gaug Markus
Published: January 2019

The Cherenkov Telescope Array (CTA) will bring a whole new insight to the gamma-ray Universe. In order to fulfill its performance requirements, we need to understand and correct the atmospheric effects that influence the acquired instrument data. One such systematic effect is due to the varying molecular density profile with time. We have studied such profiles for both CTA sites using publicly available historical data assimilation archives. Our study reveals that we can distinguish at least three differentiated seasonal periods at the northern site and at least two at the southern site, that allow to model the molecular part of the atmosphere using average profiles, as done with current Cherenkov telescope projects. Seasonal transitions are smoother at the southern site than at the northern one. Moreover, the latter shows a greater amplitude in density variations at an altitude of 15 km. We also explored deviations of the molecular profiles with respect to their mean values using a 5-years data set and concluded that they are always found within specifications.
Atmospheric monitoring with the Fluorescence detector Array of Single-pixel Telescopes
Authors: Mandat Dusan , Fujii Toshihiro , Malacari Max , Farmer John , Ni Xiaochen , Privitera Paolo , Albury Justin , Bellido Jose A. , Hamal Petr , Horvath Pavel , Hrabovsky Miroslav , Nozka Libor , Chytka Ladislav , Palatka Miroslav , Pech Miroslav , Schovanek Petr , Travnicek Petr , Matthews John N. , Thomas Stan
Published: January 2019

The Fluorescence detector Array of Single-pixel Telescopes (FAST) is a proposed low-cost, largearea, next-generation experiment for the detection of ultrahigh-energy cosmic rays (UHECRs) via the atmospheric fluorescence technique. Two FAST telescopes are currently installed and operating at the Black Rock Mesa site of the Telescope Array Experiment in Utah, USA. Knowledge of the properties of the atmosphere above the detector is of utmost importance for the analysis and reconstruction of the energy and trajectory of UHECRs measured with an atmospheric fluorescence telescope. The FAST experiment uses all sky camera (FASCam) and sky quality monitor (SQM) for the detection of clouds and quantification of the night-sky background light in the field-of-view of the telescopes. Measurements of a vertically-fired ultra-violet laser at a distance of 21 km from the FAST telescopes are used to infer the transparency of the atmosphere above the detector through comparison with simulations.
Optimization of the lidar optical design for measurement of the aerosol extinction vertical profile
Authors: Sannino Alessia , Boselli Antonella , Sasso Gaetano , Spinelli Nicola , Wang Xuan
Published: January 2019

A lidar for aerosol monitoring with conventional optical design can provide good quality signals from several hundred meters up to tens of kilometres above the ground, but the aerosol load is mainly contained (up to 80%) in the planetary boundary layer that can have a height of only hundreds of meters above the ground level. Therefore, the measurement of the complete aerosol extinction profile is generally a very difficult challenge. In this paper, we proposed an optical design of lidar systems able of producing signals starting from a few tens of meters above the ground. The overlap profiles obtained from an optimized lidar was compared with ray tracing simulations and further conventional lidar apparatuses.
The observation of lightning-related events with the Surface Detector of the Pierre Auger Observatory
Authors: Colalillo Roberta
Published: January 2019

The Pierre Auger Observatory, designed to detect ultra-high energy cosmic rays, can be a valid instrument at the ground to study phenomena related to the atmospheric electricity. The fluorescence detector is a powerful instrument to observe ELVES thanks to its excellent time resolution, while peculiar events with a large number of triggered stations have been recorded by the surface detector. The characteristic signal of these events lasts more than 10 μs, about two orders of magnitude more than the duration of a signal produced by a cosmic muon. Moreover, each of these events has at least one station with a signal dominated by a high-frequency noise that could be related with a lightning-induced signal. Stations with a long-lasting signal are arranged in a disk shape. There are “big” events characterized by a radius of about 6 km and few “small” events with a radius of about 2-3 km. The signal, generated by a source very close to the ground, first reaches the innermost stations and then spreads outwards. In the “big” events, a lack of signal in some of the central stations was observed. Further studies and checks are in progress to understand the origin of the lack of signal and what mechanisms occurring during the lightning evolution may provide for electric fields capable of generating and accelerating particles that can produce Cherenkov light in the stations of the surface detector.
Quantum computing and the brain: quantum nets, dessins d’enfants and neural networks
Authors: Asselmeyer-Maluga Torsten
Published: January 2019

In this paper, we will discuss a formal link between neural networks and quantum computing. For that purpose we will present a simple model for the description of the neural network by forming sub-graphs of the whole network with the same or a similar state. We will describe the interaction between these areas by closed loops, the feedback loops. The change of the graph is given by the deformations of the loops. This fact can be mathematically formalized by the fundamental group of the graph. Furthermore the neuron has two basic states |0〉 (ground state) and |1〉 (excited state). The whole state of an area of neurons is the linear combination of the two basic state with complex coefficients representing the signals (with 3 Parameters: amplitude, frequency and phase) along the neurons. If something changed in this area, we need a transformation which will preserve this general form of a state (mathematically, this transformation must be an element of the groupS L(2; C)). The same argumentation must be true for the feedback loops, i.e. a general transformation of states along the feedback loops is an assignment of this loop to an element of the transformation group. Then it can be shown that the set of all signals forms a manifold (character variety) and all properties of the network must be encoded in this manifold. In the paper, we will discuss how to interpret learning and intuition in this model. Using the Morgan-Shalen compactification, the limit for signals with large amplitude can be analyzed by using quasi-Fuchsian groups as represented by dessins d’enfants (graphs to analyze Riemannian surfaces). As shown by Planat and collaborators, these dessins d’enfants are a direct bridge to (topological) quantum computing with permutation groups. The normalization of the signal reduces to the groupS U(2) and the whole model to a quantum network. Then we have a direct connection to quantum circuits. This network can be transformed into operations on tensor networks. Formally we will obtain a link between machine learning and Quantum computing.
Application of design of experiment to a FCAW process
Authors: Kordas Piotr , Bęczkowski Robert , Gucwa Marek , Winczek Jerzy
Published: January 2019

This work presents the results of research on the anti-abrasion surfacing welds designated to operate under wear conditions. The main purpose of the work was to produce single-layer surface welds by means of semi-automatic hard-facing/surface welding with the use of filler material containing carbide precipitate and with the use of 10 mmand 20 mmwide beads. The samples were subject to visual and penetrant testing and to destructive testing in the form of macro and micro metallographic testing, hardness testing and bend testing with a view to determine the effect which thebeads of various widths have on the analyzed factors.
Mechanical properties of structures produced by 3D printing from composite materials
Authors: Bárnik František , Vaško Milan , Sága Milan , Handrik Marián , Sapietová Alžbeta
Published: January 2019

By 3D printing it is possible to create different structures with different fiber-laying directions. These structures can be created depending on the type of 3D printer and its software. The Mark Two printer allows printing Onyx, a material based on nylon in combination with microcarbon fibers. Onyx can be used alone or reinforced with kevlar, glass or carbon fibers. This article deals with 3D printing and evaluation of mechanical properties of printed samples.
Analysis of deformation and microstructure evolution during the cogging process of Waspaloy alloy
Authors: Kukuryk Marcin , Winczek Jerzy , Gucwa Marek
Published: January 2019

The hot deformation behavior of Waspaloy alloy has been investigated by two-pass hot cogging process. The paper presents theoretical end experimental analysis of deformations and microstructural evolutions. The results of a thermo-mechanical simulation for the spatial hot cogging process on the shaped anvils with the application of the three–dimensional finite element method, are presented. The numerical calculation gave an assessment of the effective strain, mean stress and temperature distributions in the work-piece. Models for predicting the evolution of microstructure were developed for dynamic recrystallization and grain growth phenomena. The influence of shape of the anvils on the grain size after dynamic recrystallization was analyzed. The numerical analysis was performed using a commercial program "DEFORM 3D" with thermo-mechanical and microstructural evolution coupled. The results are compared with the experimental data, a good agreement between the predicted and experimental results was obtained.
Dynamic simulation of a virtual prototype of a one-track vehicle in motion on uneven ground conditions
Authors: Łukaszewicz Krzysztof , Niechoćko Norbert
Published: January 2019

This article presents the procedure of designing and testing the virtual prototype of the one-track vehicle using the Autodesk Inventor Professional software. A multi-stage process of preparing the virtual prototype and the results of selected simulation tests were presented. During the first stage of work, a digital geometric model of the vehicle was created. The second stage includes placing the model in the dynamic simulation environment and defining the testing conditions corresponding to the actual vehicle operation conditions. The next phase relates to the realization of virtual model tests in the Autodesk Inventor dynamic simulation environment. The model was subjected to tests using the multibody systems method (MBS) to determine the forces and displacements in selected structural nodes of the vehicle, in motion on uneven ground conditions. The obtained simulation results in the form of force values over time and displacements were analyzed and conclusions were formulated. The test results can be used to conduct a more detailed endurance analysis of individual construction elements, model optimization and impact on the driver’s body. It was stated that the used method allows for a more efficient process of creating a new product and more efficient evaluation of the impact of the conditions in which it will be used.
Design of cam driving test equipment
Authors: Hren Iryna , Hejma Petr , Svijantek Honza , Soukup Josef
Published: January 2019

The work deals with the design of a test equipment designed for fatigue testing of the cutter bed. The disk cam drives the rocker, which is pressed against the cam surface by the coil spring. The test drum (buchar) copies the movement of the rocker to generate the exciting force that is loaded by the bed of the milling cutter. Based on unmatched data, the Wohler curve will be determined. This article deals only with parts of the design station. In particular, the design of the cam will be discussed here.
Kinematic analysis of Stirling engine
Authors: Vavro Ján , Vavro Ján
Published: January 2019

The submitted paper presents a kinematic analysis of Stirling engine by the vector method. Position equations are written for various points of the mechanism, and values of velocity and acceleration are obtained from derivation of the equations, depending on time. Equations in matrix form are solved by means of the Matlab program. Graphic dependences of kinematic magnitudes of some points are given in dependence on the angle of rotation of the drive member. Position equations are utilised for the animation of the mechanism. The computational model of the Stirling engine was created in the SolidWorks software program.
Investigation of railway wheelset profile wear by using computer simulation
Authors: Smetanka Lukáš , Hrček Slavomír , Šťastniak Pavol
Published: January 2019

The wear of rails and wheels is important problem in rail traffic. The change of the shape of the wheel profile has not only a great influence on the dynamic properties of the vehicle (like stability, safety by passing curved tracks, etc.), but also affects the ride comfort of passengers and environmental insults, in extreme cases it can cause rail derailment. One of the ways to predict these undesired conditions are computer aided simulation analyses. In this article are presented results of wheel profile wear by Archard wear law, when the vehicle of type Model A was driving in track by constant velocity of 30 m/s. The vehicle was traveling along track where the rail profile was defined by standard (UIC 60 profile) with cant of 1:40, or the track profile really measured on the track, the profile S 91700_16 with the cant of 1:20. Simulations were realized by SIMPACK software.
Definition of composite profiles for the needs of a dynamic analysis of a rail vehicle
Authors: Hauser Vladimír , Gerlici Juraj , Kravchenko Kateryna , Lack Tomáš , Loulová Mária , Potapenko Olha A.
Published: January 2019

When modelling the dynamics of a rail vehicle ride, one of the important input parameters is the profile geometry of the wheel and rail treads. Commonly available simulation programs have databases containing some standardized profiles, or allow the profile to be added to the database. However, complications arise when a specific profile is required in the simulation analysis. Its geometry must be entered in the form of coordinates of the knot points that can be used to render the curve and thus define the desired profile. Simulation programs, however, do not have the ability to efficiently generate these coordinates. Since this is a lengthy process, the author team has created a program to define this profiles, based on their common drawing documentation. This program allows to create even large amount of profiles needed for variable rail treads definitions of crossings and switch points by a smart way.
Analysis of the loss of vehicle motion stability in the conditions of steering control disturbance
Authors: Dudziak Marian , Lewandowski Andrzej , Śledziński Michał
Published: January 2019

Disturbances in the vehicle motion may be caused by different factors and in many cases are the reason for dangerous traffic incidents. Disturbances within the human-vehicle system are particularly hazardous. An innovative method was designed for analyzing and simulating the process of loss of vehicle motion stability after interference in the steering system, e.g. by acting on the steering wheel by the passenger. The subject of the study is the theoretical and experimental analysis of the vehicle motion path kinematics together with the duration of the disturbance, driver’s reaction time and steering wheel turning angles. PC-Crash simulation software was employed for the purpose of studying the disturbance characteristics and their influence on the loss of vehicle motion stability. It is recognized that the studied issues are as yet poorly understood, the presented results expand our knowledge base in this area and can be employed for the purpose of analysis of actual traffic accidents.
Dependence of the Cross Section of the Cut Layer on the Specific Cutting Resistance
Authors: Petrů Jana , Zlámal Tomáš , Drábek Lukáš , Hajnyš Jiří , Jurok Dalibor
Published: January 2019

This article deals with the study of the effect of cross section of the cut layer of material and its influence on the specific cutting resistance. Measurement and evaluation were carried out using two machined materials, according to the designation W.Nr. carbon steel 1.1191, which is a reference material for the steel grade and refractory nickel alloy 2.4856. For the purpose of the experiment, longitudinal turning technology with two interchangeable CNMG 120408 SM and CNMX 1204A2 – SM cutting inserts was chosen. According to the recommended index insert values, two different types of cutting conditions were chosen for each material so that the cross section of the chip remained the same during machining. For each material, the cutting speed was constant and the feed rate and cutting depth were changed. The main goal of the experimental work was comparison of the specific cutting resistance in dependence on different cross section of the removed layer of material. On the basis of measuring of cutting forces by dynamometer Kistler the resulting cutting force was determined and the size of the specific cutting resistance was calculated.
Research on the process of biomass compaction in the form of straw
Authors: Wilczyński Dominik , Malujda Ireneusz , Górecki Jan , Jankowiak Piotr
Published: January 2019

The paper presents the examination of the degree of compaction of biomass material in the form of straw, depending on the temperature of the compaction process, the diameter of the pressing punch and the humidity of the compacted straw. The series of punch-sleeve assemblies characterized by the variable diameter of both the punch and the sleeve were used in the tests. For each diameter of the sleeve, a straw sample was compressed with a force suitable to obtain a compressive stress value in the sample cross section of 10 MPa. Each punch-sleeve assembly was adapted for installation on a strength machine, mounting temperature sensors and for mounting on the surface of a cylindrical sleeve, a coil heater. Wheat-rye straw was used in the research. The tests carried out are to constitute guidelines for the construction of biomass compaction machines.
Fatigue characteristics of welded high strength steel in the low cycle region of loading
Authors: Kopas Peter , Sága Milan , Handrik Marián , Vaško Milan , Jakubovičová Lenka
Published: January 2019

Automotive industry is the one of the most rapidly developing sector of engineering. Using of new, progressive materials can make significant benefits because of growing durability and reducing weight of structural parts, which can lead to the materials and fuel savings. The authors of this paper discuss fatigue characteristics on arc metal welding process of high strength steels STRENX 700MC obtained in low cycle region (N approximate to 1.10(3) divided byN= 1.10(7) cycles) at low-frequency loading (frequency approximate to 35 Hz, T = 20 +/5 degrees C,R= -1). Authors compares results of their own experimental works and subsequently discus these result and their possible effect on the fatigue lifetime of these steels.
Compare of analytic and numerical solution of parametric oscillator with perturbation and its analytical solution
Authors: Oršanský Pavol , Ftorek Branislav
Published: January 2019

In this paper we deal with an approximative analytical solution of a second order differential equation with a fast time periodic modulation. We use for this type of the equation a homotopy perturbation method. The validity of this approximative solution is verified by numerical experiments, where we achieve considerable consistency of doth soliutions.
Plasma simulations in 2-D (r-z) geometry for the assessment of pole erosion in a magnetically shielded Hall thruster
Authors: Lopez Ortega Alejandro , Mikellides Ioannis G. , Sekerak Michael J. , Jorns Benjamin A.
Published: January 2019

Magnetic shielding of Hall thrusters has been shown to reduce erosion of the channel walls by at least a few orders of magnitude, thereby enabling the use of these devices in deep space missions. Wear tests of magnetically shielded thrusters, such as the H6 and HERMeS, have revealed that some sputtering occurs at the surface of the inner pole, a phenomenon not observed in unshielded thrusters. Even though the sputtering rates measured at the inner pole during ground testing are typically an order of magnitude lower than those found in the acceleration channel of unshielded thrusters, it is critical to understand how the source(s) of this erosion may change with operating conditions during flight. Hall2De is a 2-D axisymmetric code that makes use of a hydrodynamics formulation for both electrons and ions and assumes a quasi-neutral plasma. Since its computational domain is large enough to account for the discharge channel, poles, cathode, and plume regions, Hall2De can be used to investigate the physical mechanisms that produce the erosion of the poles. The simulation results are compared with experimental laser-induced fluorescence measurements of the ion velocity along the discharge channel of the H6 thruster. We find that the erosion of the poles in the magnetically shielded H6 is a result of the acceleration region moving outside of the discharge channel, which in turn is a consequence of a shift in the location of the maximum magnetic field along the channel centerline that occurs when magnetic shielding is implemented. When the acceleration region moves downstream, the plasma potential contours at the edges of the beam allow for high energy ions to be accelerated radially toward the pole surfaces.
pH effect on oxidation of hydrogen peroxide on Au(111) electrode in alkaline solutions
Authors: Li Jiao-jiao , Wei Jie , Cai Jun , Chen Yan-xia
Published: January 2019

The hydrogen peroxide oxidation reaction (HPOOR) on Au(111) electrode in alkaline solutions with pH values ranging from 10 to 13 was examined systematically. HPOOR activity increased and the slope of the i-E curve decreased with increasing pH. HO2− is suggested to be the main reactive intermediate for HPOOR in alkaline media. The fast kinetics for HPOOR in alkaline solution is facilitated by the electrostatic interaction between the positively charged electrode and the reactive anions (i.e., HO2− and OH−), which increases the concentration of these reactants and the thermodynamic driving force for HO2− oxidation at the reaction plane.
Comparative dietary analysis of the black-flanked rock-wallaby (Petrogale lateralis lateralis), the euro (Macropus robustus erubescens) and the feral goat (Capra hircus) from Cape Range National Park, Western Australia
Authors: Creese Sonja , Davies Stephen J. J. F. , Bowen Barbara J.
Published: January 2019

The black-flanked rock-wallaby (Petrogale lateralis lateralis) is a threatened species, once widespread throughout Western Australia but now restricted to disjunct populations including those of Cape Range National Park. It is a herbivore with a foraging range restricted to rocky outcrops and, as such, may be impacted by competition for resources from other native or introduced herbivores. This study compared the diet of the black-flanked rock-wallaby with those of co-occurring species, the euro (Macropus robustus erubescens) and the feral goat (Capra hircus), from two gorges at Cape Range National Park, to determine whether there is overlap in dietary niches. Diet composition was determined using microhistological analysis of faecal pellets in comparison with reference plant material. The black-flanked rock-wallaby diet consisted predominately of browse/forbs with some variation across seasons (63% in summer months; 74% in winter months); this overlapped significantly with the diet of goats (Schoener Index: 0.79–0.88), but not euros (SI: 0.41–0.57), whose diet consisted predominantly of grasses (72–78%). There was, however, a significant overlap in the consumption of plants with stellate hairs for all three herbivores (SI: 0.89–0.98). Dietary overlap between rock-wallabies and goats may indicate a mechanism for competition, supporting continuing measures for reduction of goat numbers in Cape Range National Park.