bluuebunny/crossref_metadata_2025 huggingface dataset:
Gaussian source coding based on variance‐mismatched three‐level scalar quantisation using Q‐function approximations
Authors: Peric Zoran , Denic Bojan , Despotovic Vladimir
Published: November 2019

This study deals with three‐level scalar quantisation of a Gaussian source, followed by Huffman encoder, especially suitable for signal compression purposes. The variance‐matched and variance‐mismatched versions of quantiser are considered. Simple approximate closed‐form expressions for performance evaluation in terms of signal‐to‐quantisation‐noise ratio and bit rate are derived using the corresponding Q‐function approximations. The accuracy of the derived formulas is tested using the relative error as a measure of performance. It is shown that the derived formulas for variance‐matched (for a reference variance) and variance‐mismatched (in a wide range of input signal variances) provide higher accuracy in comparison to baselines using other available Q‐function approximations or available approximate formulas for non‐uniform scalar quantisation of Gaussian source.
Statistics of ratios of random variables arising in analysis of wireless Poisson networks
Authors: Ermolova Natalia Y.
Published: November 2019

In this study, the author analyses statistics of some typical ratios of random variables (RVs) occurring in analysis of large‐scale wireless networks where node locations can be represented by Poisson point processes. In such networks, fading and path‐loss effects are the most important factors affecting the signal strength. The author obtains formulas for the probability density, cumulative distribution and moment generating functions of ratios of RVs occurring under many typical scenarios in cellular‐like, spectrum‐sharing, and cooperative wireless networks. All obtained results are valid for arbitrary fading models of propagation paths.
Load balancing mechanism in the cloud environment using preference alignments and an optimisation algorithm
Authors: Daming Li , Qinglang Su , Lianbing Deng , Kaicheng Cai , Zhiming Cai , Mohammed Bayan Omar
Published: November 2019

Cloud computing platforms propose applied directional information technology services to its clients. It provides services according to demands by which shared resources, data, software, and other tools are to be made available based on the client's request. Load balancing is considered as one of the main issues in cloud computing. The quality of service (QoS) factors such as resources application, answering time, process time, scalability, throughput, the durability of the system, and energy consumption are improved by the balanced load. The cloud tasks scheduling and load balancing are considered as an NP‐hard issue. Therefore, in this study, a new energy‐aware cloud load balancing method is proposed by usage of preference alignments and ant colony optimisation algorithm. This approach aims at balancing the virtual machines workload and energy consumption of cloud data centres and also assures QoS for users. CloudSim simulator is used to confirm the performance of the method. It shows that the proposed method reduces waiting time and energy consumption on a virtual machine.
Real‐time energy management in a microgrid with renewable generation, energy storages, flexible loads and combined heat and power units using Lyapunov optimisation
Authors: Zeinal‐Kheiri Sevda , Ghassem‐Zadeh Saeid , Shotorbani Amin Mohammadpour , Mohammadi‐Ivatloo Behnam
Published: November 2019

In this study, the real‐time energy management system (RT‐EMS) of a microgrid (MG) is proposed to deal with different uncertainties due to the errors in the prediction of renewable generation, load and market price. In the day‐ahead EMS, the error in prediction of data; thus, the uncertainties in the scheduling are dealt with using different scheduling methods. Nonetheless, utilising the online RT measurements is an advanced solution to eliminate the uncertainties because there would be no prediction error in employing the RT information. In this study, a RT‐EMS of a MG is designed using the Lyapunov optimisation method. In RT‐EMS, satisfying the time‐coupled constraints such as the battery energy limit and provision of load quality of service is a demanding challenge. This problem is addressed in Lyapunov optimisation by defining distinct virtual queues for satisfaction of time‐coupled constraints. Moreover, the variable V algorithm is employed to provide a better compromise between stabilising the virtual queues and the total operation cost. A test MG system consisting of combined heat and power units, renewable energy sources, energy storage systems and flexible loads is used for evaluation. The underlying distribution network and power distribution loss are further considered satisfying the voltage limits.
Optimizing the transportation route of fresh food in cold chain logistics by improved genetic algorithms
Authors: Peng Jing
Published: November 2019

At present, fresh food logistics transportation in China is still in the primary stage of development, transportation costs are rising, and cold chain logistics path design is unreasonable. Therefore, the optimization and prediction of the cold chain transportation route of fresh food has become the focus of the research in this field. Based on the principle of genetic algorithm, this paper designs an improved genetic algorithm to solve the problem of urban cold chain transportation path. In order to optimize the distribution path and minimize the total cost, a cold chain transport model is established. Through the simulation coding and calculation of the model, the influence of genetic algorithm on the optimization of the cold chain transport path is explored to reduce the cost and price of cold chain logistics transport, improve the transport efficiency, and thus improve the economic benefits of enterprises in this field. Through experiments, the optimal solution of the example is obtained, and compared with the traditional algorithm, it is proved that all the paths obtained by the improved genetic algorithm conform to the model with capacity constraint and time window constraint, and there is an optimal path for the most energy saving. In conclusion, the transport path of cold chain logistics calculated by the improved genetic algorithm is more optimized than the traditional algorithm and greatly improves the transport efficiency.
Electric Arc Surfacing of Defective Plots of Rails in the Area of Electrocontact Welded Joint
Authors: Nezhivlyak Dmitry , Nezhivlyak Andrey , Grechneva Maria
Published: November 2019

One of the main causes for the failure of the rails of a continuous joint made by electric contact welding is defects in collapse and wear in the joint zone. We address the usage of electric arc surfacing to repair defective rails. The structure and hardness are studied of the defective areas of rails recovered by electric arc surfacing performed in one and two layers. Static tests and fatigue tests of pilot samples of rails with eliminated defects were carried out. The pilot samples with defects eliminated by electric arc surfacing meet the criteria of static strength to the same degree as the rail samples without surfacing. The surfacing technology that we examined should be adjusted by applying preheating to reduce the cooling rate of metal in the weld zone. Fatigue tests showed a positive effect from surfacing at the wear sites in the welded joint. Performance tests confirm that electric arc surfacing is promising to eliminate defects in the collapse and wear of the rails in the area of the electric contact welded joint.
Forming Small Diameter Holes in Tungsten – Cobalt Alloys
Authors: Vasilevskaya Svetlana , Rakhimyanov Konstantin , Ukraintseva Alexandra
Published: November 2019

The perspectives of combining the processes of electrochemical dissolving and electro-erosive removal of the processed material in forming small diameter holes in alloy WC-8Сo by a hollow electrode-tool are presented in the paper. It is established that in using immovable electrodes forming the cone in the hole takes place. The dependence of the piercing depth change on time is obtained. It testifies the decrease in the processing speed with increasing the inter-electrode gap. It is shown that during the electro-erosive – electrochemical process with immovable electrodes the productivity of small diameter hole piercing increased by 3 times in comparison with the electrochemical processing.
Study of the Efficiency of Ultrasonic Turning of Heat-Resistant Alloys with Tools from Mineral Ceramics
Authors: Toan Nguyen Khanh , Mezin Nikolay
Published: November 2019

The results of the study of the effectiveness of high-speed ultrasonic turning of billets from heat-resistant nickel alloys without coolant are given. It was established that the introduction of ultrasonic field energy into the shaping zone reduces the contact temperature by 10–15% and the cutting force by 20–30%. However, this does not cause a decrease in metal removal performance due to a significant loss of strength and ease of cutting at temperatures above 800 C. As follows from the results, ultrasound helps to reduce the thickness of the defective layer, the formation of which is caused by thermal processes and phase transformations with the appearance of tensile residual stresses in the surface layer.
Processing Equipment on the Basis of Operative Parts in the Form of Screw Rotors With Profiled Perimeter
Authors: Lebedev Valery , Serga Georgy , Chunakhova Lidianna , Selemenev Mikhail
Published: November 2019

The main working body of technological equipment of screw rotor technological systems are screw rotors which present spatial objects with an original geometrical shape of working body perimeter in which component parts and granules of the processing environment carry out simultaneously continuous rotation around the axis of working body and progressive motion, constantly moving along a horizontal axis of working body rotation. This article gives a classification of perimeter forms of working bodies, such as screw rotors, which let to expand technological possibilities of technological equipment and to provide the increase of effectiveness of the production process by means of increase of its amplitude-frequency characteristics. The peculiarity of working bodies in the form of screw rotors is the fact that internal cavity of a rotor has a wavy shape, formed by the sides of a semicircular form. The paper covers on a construction and the principle of operation of machine-tools on the basis of working bodies in the form of screw rotors with a shaped surface on perimeter. The suggested design solutions of processing equipment allow creating highly effective machine-tools for the finishing and strengthening processing.
Mobile Processing of Pipeline Assembly Units
Authors: Safonov Sergey , Smolentsev Vladislav , Smolentseva Yana
Published: November 2019

The paper addresses the issues, related to the preparation of pipeline docking elements during the repair and recovery of pipelines in field conditions with a limited scope of technological equipment. It has been shown that the replacement of traditional processing methods by combined types of preparation of replaceable pipeline sections for welding can improve the accuracy of mating elements, preventing the occurrence of burrs at the joint. This enhances the quality of repair, ensures the tightness of pipelines, reduces the cost of operation and the period of pipeline recovery. The application of the electric-contact method of processing assembly units, based on the proposed schemes, makes it possible, without sophistication of mobile servicing means, to timely restore the performance of products, eliminating the causes of emergency situations in construction and during operation of pipelines in hydraulic systems of transport machines, especially when used under operation in high-pressure media.
Forming a regular surface topography of a cylindrical part using oscillating ironing
Authors: Zaydess Semen , Van Hin Nguen , Bobrovskij Igor
Published: November 2019

A new technological practice for the formation of a regular surface topography by means of oscillating ironing is presented. The results are based on analytical calculations and experimental studies. Surface topography after oscillating ironing depends on workpiece rotation frequency, deforming tool advance, oscillation frequency, deforming tool amplitude and tilt angle. The influence of the oscillating ironing process parameters on the size and shape of contact patch is confirmed.
Development of Technical Requirements for On-Board Cryogenic Fuel Systems of Belaz Dump Trucks
Authors: Dubov Georgiy , Trukhmanov Dmitriy , Nokhrin Sergey , Sergel Aleksey
Published: November 2019

The state-of-the-art of the issue of the efficiency and relevance of the use of liquefied natural gas (LNG) as a motor fuel in the operation of dump trucks is considered. An analysis of the benefits of using LNG as a motor fuel is given. It is noted that, LNG seems to be the most promising alternative to oil types of motor fuel in the segment of open-pit truck haulage. It is affirmed that in Russia, in Kuzbass, the group of companies successfully implemented for the first time an integrated project for the production of LNG and its consumption in relation to BelAZ dump trucks. Data on the relevance and the need to develop technical requirements for on-board cryogenic fuel systems of mine dump trucks are given. Data on the developed groups of technical requirements for on-board cryogenic fuel systems of BelAZ dump trucks are given. It is said that the developed technical requirements made it possible to solve a number of tasks related to the development of circuit and design solutions for equipping BelAZ dump trucks with cryogenic systems. It is argued that the developed technical requirements will contribute to the further development of domestic projects for the production and consumption of liquefied natural gas.
Justification of the Disk Tool Application for Working Bodies of Mining Machines
Authors: Khoreshok Alexey , Mametyev Leonid , Nesterov Valery , Tsekhin Aleksandre , Borisov Andrey
Published: November 2019

The dynamics analysis of coal mining and mine workings in Russia and Kuzbass was made with an assessment of operational productivity and load on fully-mechanized long-walls (FMLW). The article presents statistical data on the average number of FMLW and average monthly productivity of a miner. Disadvantages in the cutters work of working bodies of shearers and tunnelling machines during the mining of seams with a solid rock inclusions were determined. The usage of a disk tool instead of a cutter of working bodies of mining machines at operation at the mining enterprises of Kuzbass was offered in the article. The article recommends to expand the area of application of the mechanical method of coal seams and rocks destruction with a breaking down point of uniaxial compression up to 100 MPa by using a biconic disk tool of working bodies of extracting machines. Shearers’ tractive characteristics during mining of coal seams with rock inclusions, allowing to determine the energy intensity of destruction process by a disk tool were obtained. The options of design implementation of unified attachment points of a disc tool of working bodies of mining machines are presented. It was established that the main advantages of a disk tool over the cutter are the implementation of reversible modes of operation of working bodies, hardening and reducing dust level in face space.
Unitized Attachment Points of a Disk Tool for the Working Bodies of Shearers and Tunnelling Machines
Authors: Khoreshok Alexey , Mametyev Leonid , Nesterov Valery , Tsekhin Aleksandre , Borisov Andrey
Published: November 2019

An important task in the technological process of a mining enterprise is preparatory mine working performance, as effective operation of an entire mining complex depends on rate and quality of drilling. Therefore, the main factor affecting the performance of the process of underground mining is the correspondence of design and operating parameters of the working bodies of tunnelling machines to mining and geological conditions. The underground mining operations showed that rocks with a strength f ≤ 10 and high abrasiveness are to be destroyed with disc tools, providing higher strength, wear-resistant parameter and low dust formation in comparison with cutters. The usage of disk tools on the working bodies of tunnelling machines of selective action is a poorly studied task and requires special research of the questions of destruction, crushing and loading of rocks at reverse working modes. It has been established that researches aimed at design development of an attachment point of a disk tool for arrow-type working bodies of a tunnelling machines is an urgent scientific task. The original technical solutions for the design of the attachment points of disc and cutter tools are proposed to improve the processes of cutting of working bodies in the face massif, dust suppression, sealing and mounting-dismounting operations at the operation of shearers and tunnelling machines.
Development and Investigation of The Production Process of the Aluminum Matrix Composition Mechanically Alloyed With Single-Walled Carbon Nanotubes and the Composition Material Made of it
Authors: Vetkasov Nikolai , Kapustin Anatoliy , Sapunov Valeriy
Published: November 2019

The effect of a new suggested by authors approach for alloying of the aluminum matrix powder with carbon nanotubes is described in this paper. The manufacturing science is designed for receiving the highly-homogenous in volume dry mixture «aluminum powder – single-walled carbon nanotubes» suitable for synthetic processing of the aluminum matrix composition by the mechanical alloying and for producing of finished aluminum matrix composition materials. The effect of the experimental investigation of production processes of the aluminum matrix composition and workpieces of finished aluminum matrix composition materials is described in this paper.
Influence of the Initial State of Samples From Steel 20 on the Structural-Phase Condition to the Stable Zone Localization of Macrodeformation
Authors: Ababkov Nikolai , Smirnov Alexander , Danilov Vladimir , Popova Natalia , Nikonenko Elena , Koneva Nina
Published: November 2019

One of the most important tasks of technical diagnostics and examination of industrial safety is the problem of assessing the residual life of long-running technical devices of hazardous production facilities. The paper presents the results of the study of the structural-phase state in a stable zone of localization of macrostrains, depending on the initial state of samples from steel 20. The samples were investigated without exploitation, after operation without destruction and with destruction. The samples were stretched at the same speed until a stable zone of strain localization appeared, after which the loading was stopped. The connection is established between the processes of localization of macrostrains and the evolution of the substructural state for steel 20. It has been established that the mechanism of localization of macrodeformations is the achievement of critical values of a fragmented substructure, in other words, according to the theory of evolution of substructural transformations, a bifurcation point occurs when the % fragmented substructure prevails. The critical values of dislocation density are established, which lead to a change in the type of dislocation substructure for equipment made of steel 20.
Investigation of Electrochemical Dissolving the Amorphous and Nanocrystal Alloys by a Rotating Disk Electrode
Authors: Rakhimyanov Konstantin , Ivanova Maria , Rakhimyanov Andrey
Published: November 2019

The electrochemical processing characterized by the absence of force and heat effect on the processed material provides favorable conditions for maintaining unique properties of amorphous and nanocrystal alloys during processing. Understanding the peculiarities of the electrochemical dissolving of the material is possible in studying anode polarization characteristics. The investigations of the anode dissolving of alloys 5ВDSR and 82K3HSR conducted before showed the presence of diffusion limitations connected with the absence of the reaction products removal from the processing zone and supply a new portion of reacting substances. To eliminate the limitations, it is necessary to conduct investigations of the anode behavior by the moving electrolyte which is provided by the rotating disk electrode. It allows controlling the process of ion transfer due to the changes in the anode rotation speed and providing the accessibility of the working sample surface for the electrochemical action. The paper presents the results of polarization investigations of the anode dissolving by using the method of the rotating disk electrode in 10 % neutral solutions of salts NaNO3, Na2SO4 and NaCl. It is established that the dissolving process in the stationary and movable electrolytes is characterized by the presence of zones of slowdown of the anode dissolving process. After providing the electrolyte motion in the processing zone, it became possible to increase the value of the current density.
Mechanisms of technical ceramic density adjusting
Authors: Panteleyenko Fedor , Kuczumow Andrzej , Sieniawski Jan , Panteleyenko Katerina , Shmuradko Valeri , Korotin Vladimir
Published: November 2019

In this paper authors overviewed the most important stages of ceramics production process which give significant influence on final properties of product. Often density and porosity on the all producing stages determines exploitation ceramics properties. A calculation method for fractions ratio selection which provides optimal density is suggested here. Also, density changes during operations of grinding, forming, thermal treatment and sintering a row of specimens are researched and analysed. The data received allow to predict semi products size behaviour while producing and get definite final part with dimension required.
The Metal Surface Layer Mechanical Condition Transformation in Machining Processes
Authors: Blumenstein Valeriy , Makhalov Maxim
Published: November 2019

The metal surface layer mechanical condition transformation at the product life cycle stages key provisions are presented. The described approach feature is the hardened body effect consideration: the metal mechanical properties changing during it displacement through the deformation zone space. On the basis of the developed for surface plastic deformation process hardened elastic-plastic body model, the cumulative shear strain level, plasticity reserve exhaustion level and residual stress tensor components calculations are performed. It is established that the greatest residual compressive stresses are characteristic for the axial component, and the extremum can be located both on the workpiece surface and at some distance from it. The metal hardening influence on the residual stresses distribution is revealed. On the axial (largest) component example shown that the difference between the maximum values is almost 30%. The obtained result corresponds to the idea that the hardened metal having an increased yield strength allows a larger residual stresses presence.
Perspectives of Using Ultrasonic surface hardening in Machine Part Manufacturing
Authors: Semenova Yulia , Mazhuga Semen
Published: November 2019

The paper under consideration presents the review of the research results of different scientific schools on applying ultrasonic vibration energy. The effect of ultrasonic vibration energy on changes in the structure of surface layer material, surface topography and other characteristics are presented. A wide range of possibilities of using ultrasonic surface hardening in preparing surfaces before the chemical-thermal processing, for coating and as a finishing processing is presented. The possibilities of applying the method in the combination with other methods of affecting the material are considered. The possibilities of reducing the price of the machine part manufacturing because of implementing the operation of ultrasonic surface hardening in the technological process are shown.
Development of Mechanical Engineering in Knowledge Economy: Search for New Business Model
Authors: Zhernov Evgeny , Nekhoda Evgenia , Bruni Roberto
Published: November 2019

The purpose of the study is to propose a procedure for choosing a business model of a machine-building enterprise, depending on the degree of utilization of scientific knowledge of the company’s employees in the production. The subject of the article is the search for a new business model based on education and science in order to develop Russian mechanical engineering in the period of the emergence of the knowledge economy. At the same time, mechanical engineering is positioned as a basic branch of the knowledge economy. To select a business model, depending on the degree of use of scientific knowledge at a machine-building enterprise, a system of factors and their indicators is substantiated. The identified factors are related to possible knowledge-based business models. When choosing a business model in mechanical engineering, the most adequate to the development of the knowledge economy is the option with a high degree of utilization of scientific knowledge of workers. Therefore, the management of the system of selected factors should be aimed at the predominant use of indicators that provide this option in the production. Knowledge management is selected as the mechanism for implementing the required business model. Prospects for further research are in the organic combination of business modeling with knowledge management technologies created and applied in the dominance of the humanistic paradigm.
Improvement of Human Resource Management in the Quality Management System of the Enterprise
Authors: Mozhaeva Tatyana
Published: November 2019

The paper deals with the principles of improving the management of human resources in the quality management system (QMS) of the enterprise, based on the concept of human resources management and process approach in accordance with the requirements of international standards ISO 9000:2015. There is a dual nature of human resources identified, where the staff is considered, on the one hand, as the most important, specific resource determining the competitiveness of the enterprise, and, on the other hand, as an internal consumer of the rewarding mechanism offered to employees for quality work. The procedure to design personnel processes of QMS of the enterprise is considered. The expediency of integrating IDEF0 model and the methodology of functional cost analysis (FCA) into the enterprise’s QMS. There is no formal approach to analysis and assessment of personnel risks in the management of processes. The application of SWOT analysis adapted to the personnel management of the enterprise is justified in order to use it for controlling QMS personnel risks. There are criteria given to apply this approach to ensure the quality of personnel processes in QMS of the enterprise.
Managing Interdisciplinary Links in the Educational Environment of Technical Colleges
Authors: Kamaleeva Alsu , Nozdrina Natalya , Gilmanshina Suriya
Published: November 2019

The main methods of research are the analysis of scientific literature devoted to the problem of implementing interdisciplinary links of natural science, professional cycle disciplines, interdisciplinary courses in the institutions of secondary vocational education. To solve the integrated goal of implementing the requirements of the educational and professional standard of technical colleges we propose to use four types of interdisciplinary horizontal and vertical links, covering the subjects of natural science and general professional cycle, interdisciplinary courses, educational and industrial practice and professional standard requirements for education and training. It is proposed to distinguish four types of interdisciplinary links, aimed at solving the integrated goal of implementing the requirements of the educational and professional standard of technical colleges. In modern high-tech society there is a rapid dynamic growth of information on all branches of scientific knowledge, the emergence of new technologies and advanced forms and methods of work. These things make it difficult to identify the main and essential educational information, so the necessity to manage interdisciplinary links in the innovative educational environment of technical colleges is of primary consideration in developing modern professional Russian education.
Research on the Effectiveness of Modelling of Autonomous Flight System for Monitoring Agricultural and Industrial Sites
Authors: Nenkov Nayden , Domitrov Nedyalko
Published: November 2019

Unmanned systems (drones) have been widely used for both military and civilian purposes for many years. Knowing the capabilities of the different systems allows for the right selection in preparation for a specific task, and each task requires the correct selection of the flight system, scientific and navigation equipment. The application of these systems has grown enormously in various fields such as: leisure, information and media, monitoring and inspection (electrical, pipelines, industrial installations), geological sciences (agriculture, environment) and civil safety (search and rescue), police operations, crowd control, and more).The report describes the analysis and assessment of the feasibility of an effective model of autonomous flying systems for monitoring agricultural and industrial sites. It demonstrates the usefulness of multi-rotor unmanned systems not only in popular and advertised applications of unmanned aerial vehicles in the media, but also in agriculture. The report shows an approach for automatically adapting the system to the conditions for collecting the necessary high quality data. A model has selected that uses unmanned quad-copter, hardware platform Pixhawk and ArduPilot, designed for non-commercial videos and photos of arable land.
Organization of Personnel Training in the HR-Management System at Machine-Building Enterprises
Authors: Sushchenko Olena , Basyuk Dariya
Published: November 2019

HR management is one of the most important areas of a machine-building enterprise activity. The most important HR management functions are motivation, managing employee relations, training and development, managing employee’s quality. The personnel qualitative characteristics are reflected in the degree of professional and qualification suitability for work. Upgrading the skills of the enterprise’ personnel and their acquiring of new competencies should be based on lifelong learning system and continuous professional training. Personnel training are important part of the enterprise’s HR management system. It contributes to the development of organizational processes, the achievement of the enterprise’ goals and objectives. Personnel training aimed at their developing and motivating are a long-term investment in the enterprise employees.
Topsis Technique in Self-Government – Case Study of Košice Region
Authors: Vavrek Roman , Pukala Ryszard
Published: November 2019

In the last decades, most of the democratic countries have reallocated tax revenues from collected taxes between the state budget and local government budgets. It is possible to monitor the effort to increase the relative financial autonomy of local governments, to strengthen own revenues of local self-government and to increase the autonomy of decision-making bodies regarding their use. The manuscript focuses on usage of TOPSIS technique as a tool for comprehensive evaluation in self-government in Slovakia. 8 criteria were used and their weight was calculated based Fuller triangle method and 25 experts. Based on this analysis, it is possible to recommend this method for usage not only in public sector, but also in private sector as well. Its use is also conditioned by the appropriate selection of the monitored indicators and their weighting, which significantly determines the overall results.
Start-Ups as One of the Elements Triggering the Development of Industry 4.0
Authors: Pukala Ryszard
Published: November 2019

The study analyses the significance of start-ups in the contemporary economy in the light of the industrial revolution – Industry 4.0. It presents the essence of the fourth industrial revolution and its main components that are aimed at creating intelligent value chains on the basis of dynamic, self-organising and self-optimising sociotechnical systems. Modern information and communication technologies that are increasingly integrated with production processes are used to this end. In this aspect, new digital client access channels are of key significance, as they allow departing from the traditional “push” model (pushing products into the market) and moving towards the “pull” model (production on demand). Start-ups play an important role as regards these relationships, since they operate in an ecosystem tailored to their needs and, as a result, they become more important in creating digital business models. These models, in turn, enable them to gain competitive advantage under volatile market conditions. Competition is an immanent feature of start-ups: operating under in an environment marked by high risk forces them to accept challenges that lead them to achieving market success and stable long-term development. The results of conducted analyses indicate that competition, treated as the main hazard for the operation and development of start-ups, depends on the developmental status of such enterprises and their market lifespan.
Technology to Increase Hydrocarbon Wear Resistance of Friction Units of Hydrogen Aggregates
Authors: Shalygin Mikhail , Kuznetsov Sergei
Published: November 2019

The causes of hydrogen wear of the friction surfaces involved in hydrocarbon transfer and distillation processes are considered. Some technological methods for reducing the hydrogen wear of parts and friction units operating in hydrocarbon environment are given. A comprehensive technology for obtaining the properties of the surface layer is proposed, which provides an increase in the wear resistance of a friction pair and smoothing the surface roughness. The increase in wear resistance is based on several mechanisms: (1) decreasing biographical hydrogen due to the dehydration process; (2) smoothing surface irregularities by saturating the surface with silicon; (3) reducing the diffusion capacity of the steel surface caused by diffusion siliconizing; (4) reducing grain size of the material. Comparative wear tests were carried out, which showed the effectiveness of the proposed methods.
Mechanism of Chip Formation Process at Grinding
Authors: Shumyacher Vyacheslav , Kryukov Sergey , Kulik Olga , Kennedy Xavier
Published: November 2019

The mechanism of chip formation process at grinding is described, which involves a high-speed interaction of abrasive grain and metal, which leads to a concentration of thermal energy in front of the dispersing element (grain), causing a locally concentrated shift in the metal microvolume. In “abrasive grain -metal” contact a dissipative structure is formed which existence is supported by exchange of energy and substance with environment. Due to shock compression of the metal microvolume with abrasive grain, shock-wave heating is realized, initiating emission of electrons ionizing the lubricating cooling fluid in the zone of formation of side micro-scratches left by abrasive. The results obtained in the course of the research can be used to explain the mechanisms of chip formation, as well as the course of the physical and mechanical processes occurring on the surface layers of the grinded workpieces. By controlling chip formation processes at high-speed grinding, by optimally selecting the appropriate ratios between cutting speed and other processing parameters, a reduction in process thermal density can be achieved, which, with the highest productivity, will allow to obtain the required quality of the surface layer of the workpieces and a given dimensional accuracy.
Distilled water and ethyl alcohol boiling heat transfer on selected meshed surfaces
Authors: Dąbek Lidia , Kapjor Andrej , Orman Łukasz J.
Published: November 2019

The article deals with the problem of pool boiling heat transfer enhancement on metal wire mesh coatings made of copper and phosphor bronze at nucleate boiling of distilled water and high purity ethyl alcohol under ambient pressure. The tests have been performed on horizontal samples containing different microstructures produced with the sintering technology. The samples were attached to the heating block with soldering. As a result of the experiments, boiling curves were obtained, describing the relationship between the dissipated heat flux and the superheat values for each specimen. A considerable augmentation of heat flux has been recorded for the meshed surfaces in relation to the smooth reference surface without any coating. Generally, the highest enhancement was recorded for the low superheat values. The presented test results have been discussed and then compared with selected correlations available in literature for nucleate boiling heat transfer on microstructure coated surfaces.
Determination of whole-body tumour burden on [68Ga]PSMA-11 PET/CT for response assessment of [177Lu]PSMA-617 radioligand therapy: a retrospective analysis of serum PSA level and imaging derived parameters before and after two cycles of therapy
Authors: Michalski Kerstin , Mix Michael , Meyer Philipp T. , Ruf Juri
Published: November 2019

Aim In patients with metastasized castration-resistant prostate cancer a reliable imaging-based therapy response assessment in addition to PSA kinetics is desirable. Recently, measurements of whole-body tumour burden by [68Ga]PSMA-11 PET/CT have been reported for response assessment in oligometastasic patients. The present study investigated the association of PSMA PET derived parameters and serum PSA level before and after [177Lu]PSMA-617 radioligand therapy (RLT).

Methods This retrospective study assessed whole-body PSMA tumour volume (PSMA-TV) in 10 patients with multifocal to diffuse metastases before and after 2 cycles of RLT using volume of interest (VOI) analysis. A standardized uptake value (SUV) threshold-based approach was used to semi-automatically delineate all voxels with a SUV ≥ 2.0 g/ml using the software ROVER® (ABX Radeberg, Germany). Voxels with physiological tracer uptake (e. g. kidneys) were excluded manually. Correlations between PSMA-TV and serum PSA level before and after two cycles of RLT as well as changes thereof (ΔPSMA-TV and ΔPSA, respectively) were calculated.

Results Changes of ΔPSMA-TV and ΔPSA were concordant in 7 of 10 patients. Whereas a good correlation was found between PSMA-TV and PSA before RLT (ρ = 0.81, p = 0.0049), this correlation was attenuated after RLT (ρ = 0.64, p = 0.0479). Consequently, no association was found between ΔPSMA-TV and ΔPSA (ρ = 0.39, p = 0.26).

Conclusion The attenuation of the correlation of PSA and PSMA-TV after RLT suggests that in patients with advanced disease the comparison of imaging based parameters such as PSMA-TV and PSA level might be useful for an adequate monitoring of treatment response.
Recyclable Heterogeneous Palladium-Catalyzed Carbonylative Cyclization of 2-Iodoanilines with Aryl Iodides Leading to 2-Arylbenzoxazinones
Authors: Xu Zhaotao , Huang Bin , Zhou Zebiao , Cai Mingzhong
Published: November 2019

A highly efficient and practical heterogeneous palladium-catalyzed carbonylative coupling of 2-iodoanilines with aryl iodides has been developed. The reaction occurs smoothly in toluene at 110 °C with N,N-diisopropylethylamine as base under carbon monoxide (5 bar) and offers a general and powerful tool for the construction of various valuable 2-arylbenzoxazinones with excellent atom-economy, high functional group tolerance, good to high yields, and easy recyclability of the palladium catalyst. The reaction is the first example of heterogeneous palladium-catalyzed carbonylative coupling for the preparation of diverse 2-arylbenzoxazinones from commercially easily available 2-iodoanilines and aryl iodides.
Synthesis of Spirofluorenyl-1,2,4-oxadiazinan-5-ones through Metal-Free [3+3] Cycloaddition of N-Vinyl Fluorenone Nitrones with Aza-oxyallyl Cations
Authors: Luo Yan , Chen Chun-Hua , Zhang Jin-Qi , Liang Cui , Mo Dong-Liang
Published: November 2019

Spirofluorenyl-1,2,4-oxadiazinan-5-ones are prepared in good to excellent yields through metal-free [3+3] cycloaddition of N-vinyl fluorenone nitrones and aza-oxyallyl cations under mild reaction conditions. Detailed studies reveal that N-vinyl fluorenone nitrones show greater reactivity in [3+3] cycloadditions with aza-oxyallyl cations compared to N-alkyl/aryl fluorenone nitrones. The spirofluorenyl-1,2,4-oxadiazinan-5-ones are easily prepared on gram scale. The present method features mild reaction conditions, broad substrate scope, good functional group tolerance and efficient [3+3] cycloadditions of 9-fluorenone nitrones.
Combined electrokinetic manipulations of pathogenic bacterial samples in low-cost fabricated dielectrophoretic devices
Authors: Martínez-Brenes Alejandro , Torres-Castro Karina , Marín-Benavides Richard , Acuña-Umaña Katherine , Espinoza-Araya Christopher , Ramírez-Carranza Raquel , González-Espinoza Gabriela , Rojas-Campos Norman , Guzmán-Verri Caterina , Sáenz-Arce Giovanni , Lesser-Rojas Leonardo
Published: November 2019

A low-cost fabrication method of microfluidic devices with micrometer-sized constrictions used for electrodeless dielectrophoresis (eDEP) is demonstrated here. A structure on a commercial printed circuit board (PCB) template of one-sided copper clad fiberglass-epoxy laminate was used as a molding master for polydimethylsiloxane (PDMS) soft lithography. This was achieved by printing a constriction-based microchannel pattern on glossy paper with a micrometer-scaled resolution laser printer and transferring it to the laminate’s Cu face, rendering a microstructure of ∼17 µm height and various widths across tips. The Cu master’s pattern was transferred to PDMS, and smooth constrictions were observed under the microscope. Following air plasma encapsulation, PDMS chips were loaded with an inactivated bacterial sample of fluorescently stained Brucella abortus vaccine strain S-19 and connected to an amplified voltage source to examine the sample’s response to electric field variations. After an AC/DC electric field was applied to the bacterial solution in the microfluidic device, the combined effect of electrokinetic + hydrodynamic mechanisms that interact near the dielectric microconstrictions and exert forces to the sample was observed and later confirmed by COMSOL simulations. Our fabrication method is an alternative to be used when there is no access to advanced microfabrication facilities and opens ways for target selection and preconcentration of intracellular pathogens as well as sample preparation for metagenomics.
Microfiber-shaped building-block tissues with endothelial networks for constructing macroscopic tissue assembly
Authors: Kurashina Yuta , Sato Ryo , Onoe Hiroaki
Published: November 2019

We describe a microfiber-shaped hepatic tissue for in vitro macroscopic tissue assembly, fabricated using a double coaxial microfluidic device and composed of cocultured Hep-G2 cells and human umbilical vein endothelial cells (HUVECs). The appropriate coculture conditions for Hep-G2 cells and HUVECs in the microfiber-shaped tissue were optimized by changing the thickness of the core and the cell ratio. The HUVEC networks were formed in the microfiber-shaped tissue following culture for 3 days. Using this microfiber-shaped tissue as a building block, two types of macroscopic assembled tissues were constructed—parallel and reeled tissues. In both tissue types, the connection of the HUVEC network across the adjacent microfiber-shaped tissues was established after 2 days, because the calcium alginate shell of the microfiber-shaped tissue was enzymatically removed. Our approach could facilitate the generation of complex and heterogeneous macroscopic tissues mimicking the major organs including the liver, kidney, and heart for the treatment of critically ill patients.
Microscopic origin of multiple exciton emission in low-dimensional lead halide perovskites
Authors: Du Mao-Hua
Published: November 2019

Low-dimensional halide perovskites exhibit intriguing excitonic properties and emerge as an important class of self-activated luminescent materials. However, the ability to manipulate and optimize their luminescent properties is limited by the lack of the microscopic understanding of the exciton relaxation and emission and the inconsistency in the theoretical results in the literature. In this work, based on first-principles calculations, we studied excitons in 1D lead halide perovskites, C4N2H14PbBr4 and C4N2H14PbCl4, which are both bright visible-light emitters. We find that, in both compounds, the polaron-pair exciton (EX-PP) is more stable than the onsite exciton (EX-OS) and only the EX-PP emission energy from the calculation is close to the main photoluminescence (PL) peak observed in the experiment. The EX-OS is found to emit UV light in both compounds. Therefore, the EX-PP is responsible for the experimentally observed visible light emission in both C4N2H14PbBr4 and C4N2H14PbCl4. Furthermore, the calculated small energy difference between the EX-PP and EX-OS in C4N2H14PbBr4 suggests that the metastable EX-OS can be thermally populated at room temperature (RT); the calculated EX-OS emission energy agrees well with the energy of a minor PL peak observed at RT but not at 77 K. The validity our approach in the exciton calculation is supported by the benchmark of the calculated exciton emission energies against the experimental results in 13 0D and 1D metal halides. The discrepancies between this work and a recent theoretical study in the literature are also discussed.
Electronic transport and spatial current patterns of 2D electronic system: A recursive Green’s function method study
Authors: Zhang X. W. , Liu Y. L.
Published: November 2019

Based on the scanned probe microscopes, the local current properties in a nanodevice can be clearly exposed. However, it is still a big challenge to experimentally observe the atomic scale varying current pattern. A numerical-aided method is therefore very important for getting the local current information in a microsystem. In this study, we show the nonequilibrium Green’s function method to calculate the transport properties of two-terminal devices. For applying this method to larger systems, a recursive procedure is present in detail. The correctness of this method is confirmed by calculating the transport properties of a clean 2DEG. The conductance steps in such a sample match the corresponding band structure very well. Then, we calculate the current patterns in quantum point contact under a saddle-point potential. Several current jets can be clearly spotted which correspond to transport channels in quantum point contact. Meanwhile, the interference streaks are spotted near the edges of the device due to the reflection of electrons at the edges.
Étale monodromy and rational equivalence for -cycles on cubic hypersurfaces in
Authors: Banerjee K. , Guletskiĭ V.
Published: November 2019

Letbe an uncountable algebraically closed field of characteristic, and letbe a smooth projective connected variety of dimension, embedded intoover. Letbe a hyperplane section of, and letandbe the groups of algebraically trivial algebraic cycles of codimensionandmodulo rational equivalence onand, respectively. Assume that, wheneveris smooth, the groupis regularly parametrized by an abelian varietyand coincides with the subgroup of degreeclasses in the Chow group. We prove that the kernel of the push-forward homomorphism fromtois the union of a countable collection of shifts of a certain abelian subvarietyinside. For a very general hyperplane sectioneitherorcoincides with an abelian subvarietyinwhose tangent space is the group of vanishing cycles. Then we apply these general results to sections of a smooth cubic fourfold in.

Bibliography: 33 titles.