Technical Realization Research Articles

Vacuum Arc Plasma Coating for Polymer Surface Protection— A Plasma Enhanced In-Orbit Additive Manufacturing Concept

In-orbit additive manufacturing (AM) is a promising approach for fabrication of large structures. It allows to expand and accelerate human space exploration possibilities. Extrusion-based AM was demonstrated in zero gravity, while the realization of such a process in orbit-like vacuum conditions is currently under exploration. Still, a solution for protection of the UV and IR radiation sensitive polymers is needed in order to prevent their early mechanical failure under space conditions. Vacuum arc plasma based process is widely applied on earth for thin protective coating deposition. Its major advantage is its scalability—from tiny size used in electric propulsion to large scale coating devices. The usability of the vacuum arc process in space conditions was shown in electric propulsion applications in nano-satellites. In this work we discuss and demonstrate the integration of vacuum arc process as a post processing step after Fused Filament Fabrication (FFF) for additive manufacturing and functionalization of long polymer structures. Here we address the concept for technical realization, which integrates the vacuum arc into additive manufacturing process chain. More over we present a laboratory prototype, which implements this concept together with a use case, where a previously printed PEEK structure is coated with aluminum based coating suitable for UV radiation protection.

Longitudinally Heterogeneous Tumor Dose Optimizes Proton Broadbeam, Interlaced Minibeam, and FLASH Therapy.

Simple SummaryThe aim of any kind of external radiation therapy is to control a tumor with the highest possible probability of the lowest possible side effects. Here, we study further opportunities of reducing the side effects of proton therapy by applying longitudinally heterogeneous dose distributions in the tumor respecting the delivery of a minimum prescribed dose. In our simulations, the longitudinally heterogeneous dose distributions show a reduced dose in the healthy tissue already in the case of proton broadbeam irradiations, but a much higher (calculated) mean cell survival in the case of proton minibeam irradiation. This demonstrates its potential to substantially reduce side effects at a simultaneously higher tumor control probability, opening new opportunities of easier application when striving for high dose-rate applications of proton beams (>~10 Gy/s), in order to additionally profit from the so-called FLASH effects.The prerequisite of any radiation therapy modality (X-ray, electron, proton, and heavy ion) is meant to meet at least a minimum prescribed dose at any location in the tumor for the best tumor control. In addition, there is also an upper dose limit within the tumor according to the International Commission on Radiation Units (ICRU) recommendations in order to spare healthy tissue as well as possible. However, healthy tissue may profit from the lower side effects when waving this upper dose limit and allowing a larger heterogeneous dose deposition in the tumor, but maintaining the prescribed minimum dose level, particularly in proton minibeam therapy. Methods: Three different longitudinally heterogeneous proton irradiation modes and a standard spread-out Bragg peak (SOBP) irradiation mode are simulated for their depth-dose curves under the constraint of maintaining a minimum prescribed dose anywhere in the tumor region. Symmetric dose distributions of two opposing directions are overlaid in a 25 cm-thick water phantom containing a 5 cm-thick tumor region. Interlaced planar minibeam dose distributions are compared to those of a broadbeam using the same longitudinal dose profiles. Results and Conclusion: All longitudinally heterogeneous proton irradiation modes show a dose reduction in the healthy tissue compared to the common SOBP mode in the case of broad proton beams. The proton minibeam cases show eventually a much larger mean cell survival and thus a further reduced equivalent uniform dose (EUD) in the healthy tissue than any broadbeam case. In fact, the irradiation mode using only one proton energy from each side shows better sparing capabilities in the healthy tissue than the common spread-out Bragg peak irradiation mode with the option of a better dose fall-off at the tumor edges and an easier technical realization, particularly in view of proton minibeam irradiation at ultra-high dose rates larger than ~10 Gy/s (so-called FLASH irradiation modes).

Towards a hybrid user interface for the visual exploration of large biomolecular networks using virtual reality.

Biomolecular networks, including genome-scale metabolic models (GSMMs), assemble the knowledge regarding the biological processes that happen inside specific organisms in a way that allows for analysis, simulation, and exploration. With the increasing availability of genome annotations and the development of powerful reconstruction tools, biomolecular networks continue to grow ever larger. While visual exploration can facilitate the understanding of such networks, the network sizes represent a major challenge for current visualisation systems. Building on promising results from the area of immersive analytics, which among others deals with the potential of immersive visualisation for data analysis, we present a concept for a hybrid user interface that combines a classical desktop environment with a virtual reality environment for the visual exploration of large biomolecular networks and corresponding data. We present system requirements and design considerations, describe a resulting concept, an envisioned technical realisation, and a systems biology usage scenario. Finally, we discuss remaining challenges.

Investigating the Influence of the Diffraction Effect on Fourier Transform Spectroscopy with Bandpass Sampling

Fourier transform spectroscopy with bandpass sampling (BPS-FTS) increases the interferogram sampling step and reduces sampling frequency, thereby reducing system implementation difficulty. However, this technology has only been introduced in principle and lacks analysis of the actual system error. In this paper, we present a theoretical analysis of the optical system diffraction effect, derive the bandpass spectrum bandwidth and interferogram sampling step under the influence of the diffraction effect, and conduct modeling and a simulation analysis with and without the diffraction effect. Through simulation, we found that when the diffraction effect was considered, the relative deviation of the recovered spectrum from the input spectrum was 1.30%, and the spectral similarity was 0.9669. However, without considering the diffraction effect, the relative deviation of the recovered spectrum from the input spectrum was 6.23%, and the spectral similarity was only −0.0056. The simulation results demonstrate that the diffraction effect has a significant influence on BPS-FTS interferogram sampling and recovery spectra. The results of this study have reference significance for their technical realization of BPS-FTS.

Modification of the weld penetration characteristics in laser deep welding by the use of instationary gas flows

The present report focuses on the integration of a technology for generating temporally alternating (pulsed) gas flows in the field of laser welding. The technical realization required the specific adaptation of the three core elements of the gas pulse system (valve, section of measurements, control system) to realize new parameters for laser welding. These parameters allow for a positive influence on the joining process and on the results of welding, respectively. By means of temporal control of the gas volume flow in combination with the laser welding process, it was possible to produce a force effect on the molten pool and subsequently to improve the characteristics of laser-welded seams. The effects occurring through the use of an instationary gas flow were evaluated by using the "classically" metallography and through the use of digital image processing. In parallel, the effect of a pulsating gas flow on the melting zone was simulated by using specific software in order to be able to make further statements about the effects.

Ontology modeling method applied in simulation modeling of distribution network time series operation

Aiming at the difficulties in the realization of timing simulation in the digital twin environment, this article proposes an ontology modeling method applied to the simulation modeling of distribution network timing series operation. First, the two-layer ontology modeling architecture is introduced, and the power system domain structure ontology and the business-based application ontology are constructed. Second, based on the dynamic ontology modeling method, combined with the operational simulation business requirements, the sequential operation simulation ontology model is dynamically constructed. Finally, the effects of the modeling method in terms of simulation expression and modeling efficiency are shown through practical application example, and the modeling methods are compared and analyzed. The results provide a reference for the technical realization of power grid modeling in digital twin environments.

The need for monitoring mineral fertilizers for the content of pollutants

The possible danger of fertilizers used in agriculture as a source of heavy metals (HM) soil pollution, is analyzed in the article. The absence of any control/ monitoring system in Ukraine makes this danger possible. The literature analysis testifies that dangerous and very dangerous HM contain level in Ukrainian soils is determined at the area of 1,606 thousand hectares. Except the elements being detected and determined in agrochemical pasportisation program. the fertilizers or raw minerals nickel (Ni), arsenic (As), bromine (Br). chrome (Cr). Amongst these elements, only arsenic is being testified in the agricultural production (grain, fruits and berries, vegetables, forage; the rest is out of control. Complex fertilizers, besides, may contain fluorine (F) and strontium (Sr), at least non-radioactive. Certain amount of toxic metals is being absorbed by soil colloids, but thus their stepby-step release, and respectively presence in soils is enabled. Toxic elements contain in fertilizers depends, first of all on their production technology, as well as raw origin. Raw materials being sanctioned today, and originated from Russia, are most clear amongst those from other regions (North Africa). Industry and transport are also well-known as the environment pollution source, and this source cannot be controlled by agricultural growers. But it is possible to provide control of pollutants reaching soil seems to be quite real; where the organizational efforts are needed. In Ukraine the legislative basis which specifies the obligate control of the fertilizers pollution level, the register and content level of pollutants is absent. Also, the radiology level control is also actual. It is necessary, first of all, to solve the legislation basis problem, then the technical realization should be. The «Soil Protection Institute of the Ukraine» is competent enough with staff and equipment, to enable the staterun control under the HM level content in fertilizers, and at least sampling radiology control. The same concerns the raw minerals used in fertilizers production, so as it could help the fertilizers manufacturer to avoid possible problems in future.

Performance evaluation of German smart meter infrastructure for load management through grid operators

The transition to a climate-neutral energy system involves the integration of many small components—on the generation as well as on the consumption side. Their controllability is a crucial part of running a reliable energy system, for example, to prevent or resolve grid congestions. The smart meter infrastructure enables a secure integration of these small system units in grid operator processes. The technical realization of German smart meter infrastructure is detailed in the guidelines of the German Federal Office for Information Security. It must undergo certification before being deployed. In order to assess whether the standardized German infrastructure meets the requirements for the use case, we conducted a performance analysis including the three factors “overall reliability”, “emerging data volume”, and “latency time”. The investigated use case is “Load Management through Grid Operators”. For data collection, we used log records from all participating devices along the process chain and recorded all network traffic. In total, we executed over 2000 commands within the test series and analyzed over 3.0 mio. data points. We concluded 98.2% successful power limitations for the overall reliability. The average emerging data volume is 14.97 kB when executing one command within one communication session. The latency time from the command until the reaction is on average 51 s, referring to the case of a curative power limitation and needing to establish a communication channel. Thus, the requirements for the considered use case are fulfilled, provided that the capacity of communication infrastructure is made available according to the number of controllable components.

Towards a Counting Point Detector for Nanosecond Coherent X-ray Science

We present the technical realization of a high-speed hard X-ray single-photon counting-detection scheme based on a commercial avalanche silicon photodiode and high-speed oscilloscope. The development is motivated by the need to perform pulse-resolved photon-correlation and pump-probe studies at synchrotron sources with densely packed pulse patterns that result in high repetition rate pulses on the order of hundreds of MHz. Commissioning experiments are performed at the 1C PAL-KRISS beamline at PLS-II of South Korea operating at a burst mode maximum repetition rate of 500 MHz. In such a high count-rate measurement, detector dead-time can lead to a distortion of counting statistics. We are able to model the counting behavior of our detector under these conditions with a detector dead-time comparable to time between X-ray pulses, implying that nanosecond X-ray photon correlation spectroscopy should be possible at diffraction-limited light sources.

Water-ethanol blending effects on combustion performance of methane-air premixed-flame burners

• Water and ethanol vapors were supplied to a methane-air premixed-flat-flame burner. • Flame stabilization of ceramic-honeycomb and metal-fiber burners were studied. • Simulated CO/NO emissions were compared and radiative heat transfer was examined. • Lifecycle CO 2 and NOx could be reduced with sufficient stability and efficiency. Recently, water injection into the recuperator of a condensing boiler was employed to achieve higher thermal efficiency and lower NOx emission simultaneously. In addition, biofuel blending was adopted to reduce the lifecycle CO 2 emission. In this study, injection of a water-biofuel mixture into a condensing boiler was proposed to provide both advantages simultaneously. Ethanol was selected as the surrogate of a water-miscible biofuel. As an essential step in its technical realization, the combustion performances of methane-air premixed-flame burners were examined with variations in the concentrations of methane, ethanol, and water. Flame stabilization characteristics were examined for two kinds of burners: a ceramic-honeycomb burner and a metal-fiber burner. The effects of water and ethanol blending on CO and NO emissions were examined. The product gas had an orangish light, and its emission spectra and emissive power were investigated. Conclusively, it was shown that blending water with a miscible biofuel (or ethanol) could reduce the lifecycle CO 2 emission and achieve the better combustion performances required for commercial premixed-flame burners of condensing boilers. A mixture of the same water and ethanol vapor volume could reduce NO by 70%, and ethanol blending with methane could increase radiative heat transfer from the product gas by approximately 20%.

Energy Efficiency of Resistive High Field Magnets: Aspects of Magnet Technology, Power Supply Operation and Field Quality

The design and operation of resistive high field magnets require research and development in materials science, power supply engineering and instrumentation. Recently, their energy efficiency has become a very important concern. In our contribution we report on recent advances on an energy efficient use of the 24 MW resistive magnets at the French National High Magnetic Field Laboratory at Grenoble (LNCMI) that can reduce their energy consumption by up to 20%, for a given user experiment. This saving is possible due to a special architecture of the LNCMI high field magnets. Namely, the total magnetic field is provided by two independent concentric sub magnets exhibiting different field characteristics, i.e., absolute field values for a given current and spatial field distributions. As both sub-magnets can be powered in an independent way, their currents can be tuned to minimize the total electrical power for a target magnetic field requested by the user. This enables energy efficient operation. However, the consequences of strain enhancement on magnet safety and life time due to higher current densities in the inner sub magnet have to be considered. LNCMI magnet design, power supply and instrumentation teams have recently implemented this innovative operation mode in a collaborative project. We will present its technical realization including electrical power modelling, magnet load estimations as well as first benchmark experiments including NMR. Finally, we will discuss the perspectives of this operation mode for innovative user experiments.

Flame coatings by CCVD (Pyrosil) for R2R applications

Flame coatings by CCVD (Pyrosil) for R2R applications

Digital model of radiocephalic arteriovenous fistula for decision support and improvement of maturation

The native arteriovenous fistula (AVF) is the recommended first intention vascular access in dialysis patients. This non-physiological surgical construction implies many anatomical and hemodynamic parameters. Radio-cephalic AVFs are preferred due to a low rate of long-term complications. The early rates of thrombosis and failure of maturation of the distal AVFs remain high, between 20 and 50%. The aim of this work was to obtain a faithful digital model simulating the flow of a radiocephalic AVF to guide the surgeon in the choice and the technical realization of AFVs in order to improve maturation.

DCIV: Decentralized cross-chain data integrity verification with blockchain

In recent years, blockchain holds promise to impact a wide range of application areas, but it still suffers from technical challenges such as security and scalability. The increase in the number of transactions puts blockchains under data storage pressure. The emergence of cross-chain technologies connects different blockchains and relieves the data storage pressure. However, the existing research generally focuses on the technical realization of cross chain, lacking in-depth research on consistency issues like data integrity verification of cross-chain interaction. In this paper, we propose a decentralized cross-chain data integrity verification scheme (DCIV) from the point of view of governing the chain by chain. We adopt supervision chain to audit the integrity of data in cross-chain interaction. We preprocess the off-chain original data in the form of Merkle tree. Before cross-chain interaction, we process the data with KZG polynomial commitment. During the auditing period, the supervision chain generates a challenge and verifies the integrity of cross-chain data. In particular, we add audit digests into the structure of transactions in blockchain to reduce the storage burden during auditing. Theoretical and experimental analyses demonstrate that DCIV can verify the integrity of data in cross-chain interaction, achieving secure and accurate cross-chain data sharing.

Automated identification of different lead users regarding the innovation process

Lead users are often established in an organizational innovation process to attenuate the difficulties a company faces, such as high costs or the obscurity of customers’ needs. But to benefit from these lead users a major challenge is to characterize and identify them especially in the fast-moving world of social media. Therefore, we aim to design a tool to identify lead users automatically for the two innovation phases (“Idea generation” and “Development”) by combining different approaches such as social network analysis, topic modeling and sentiment analysis. Thus, we consulted the design science approach and applied our artifact to 11,481 contributions of an online digital platform. The technical realization of the six different characteristics and their respective weighting according to the different phases of the innovation process resulted in different lead users and showed the necessity of distinguishing between them. Our results were evaluated and confirmed by the identified lead users and an expert. Hence, our investigation contributes to both practice and theory (kernel theories and design theory) alike.

Analytical determination of energy intensity of critical deep cutting of soils by multi-scraper trench excavators

The object of research is the processes of interaction of the cutters of the working body of the chain trench excavator on the basis of the semi-blocked critical depth mode of soil cutting. One of the most problematic places is that the known analytical and experimental models of interaction of multi-scraper chain trench excavators with soil do not determine the parameters and modes of their operation based on critical depth cutting of soils. Therefore, the design of work equipment for given conditions on the basis of such dependencies does not provide the minimum energy consumption and maximum productivity of the work process. The research used the method of analytical calculation of parameters of installation of soil-developing elements and determination of energy performance of multi-scraper chain working body of trench excavator on the basis of semi-blocked critical-depth soil cutting regime. The proposed calculation method allows to determine the parameters of installation of the working body and placement of soil development elements and to quantify the energy performance of multi-scraper chain working body of the trench excavator based on semi-blocked critical depth of soil cutting mode. The obtained method of calculation, in contrast to existing empirical estimates, allows developing options for improving the parameters of multi-scraper chain working body. As a substantiation of this conclusion the conceptual variant of technical realization of the working equipment is offered, namely, allows to prove expediency of the choice of the semi-blocked scheme of arrangement of cutters of critical deep cutting of soil of a working body of a trench multi-scraper excavator. The conducted energy analysis showed that it is more expedient to use a multi-scraper chain working body of a trench excavator on the basis of a semi-blocked critical-depth regime of soil cutting. For example, for soil semi-solid clay with blocked cutting, cutting angle αc=20–30°, cutter width b=0.02 m the energy intensity of the working process varies within E=191–233 kJ/m3; for semi-blocked cutting under the same conditions – E=187–191 kJ/m3, which is 2–18 % less.

The Interface of Privacy and Data Security in Automated City Shuttles: The GDPR Analysis

The fast evolution and prevalence of driverless technologies has facilitated the testing and deployment of automated city shuttles (ACSs) as a means of public transportation in smart cities. For their efficient functioning, ACSs require a real-time data compilation and exchange of information with their internal components and external environment. However, that nexus of data exchange comes with privacy concerns and data protection challenges. In particular, the technical realization of stringent data protection laws on data collection and processing are key issues to be tackled within the ACSs ecosystem. Our work provides an in-depth analysis of the GDPR requirements that should be considered by the ACSs’ stakeholders during the collection, storage, use, and transmission of data to and from the vehicles. First, an analysis is performed on the data processing principles, the rights of data subjects, and the subsequent obligations for the data controllers where we highlight the mixed roles that can be assigned to the ACSs stakeholders. Secondly, the compatibility of privacy laws with security technologies focusing on the gap between the legal definitions and the technological implementation of privacy-preserving techniques are discussed. In face of the GDPR pitfalls, our work recommends a further strengthening of the data protection law. The interdisciplinary approach will ensure that the overlapping stakeholder roles and the blurring implementation of data privacy-preserving techniques within the ACSs landscape are efficiently addressed.

Artificial Intelligence and VR Environment Design of Digital Museum Based on Embedded Image Processing

This article first introduces the development of embedded image processing system, puts forward the overall design of the system structure, constructs the development environment of software system and hardware, and introduces in detail the choice of embedded image processing system and artificial intelligence embedded operating system in the industry, the choice of objective lens, and the choice and installation of the light source in the system. According to the system requirements, the design, function, and working method of the GPIO peripheral circuit are introduced in detail, and the circuit diagram and PCB diagram of the GPIO peripheral expansion circuit are provided. Based on this, this article focuses on the technical realization of 3D landscape modeling technology, 3D landscape rotation technology, digital museum dynamic scene fusion technology, interactive animation perception over time, real visual virtual landscape, and virtual roaming scene perception in detail. The 3D landscape modeling technology and the modeling method of digital museum environment in virtual reality in this article are used to analyze and study the general concept of VR environment design in virtual reality environment and make it based on different characteristic methods of different modeling. The overall structure and theoretical basis of the VR environment in the digital museum are based on technical solutions, such as process modeling and scene structure. This technical solution has been verified in practical applications and is achievable. Regarding image recording, this paper proposes an improved image-based recording method. In terms of image coupling, this article uses an improved progressive input and output algorithm that can use CRML to create simple dynamic scenes, which can create clear and vivid animation effects, so that the viewer has a good experience.

ИДЕНТИФИКАЦИЯ КОДОВЫХ СИГНАЛОВ АВТОМАТИЧЕСКОЙ ЛОКОМОТИВНОЙ СИГНАЛИЗАЦИИ НА ОСНОВЕ МАШИННОГО ОБУЧЕНИЯ

Stability of railway automation systems, utilizing automatic locomotive signaling as a mean for interval regulation of train traffic, can be risen by the means of application of machinal training algorithms. Known algorithm for code signal identification of locomotive signaling has a row of drawbacks which are conditioned by the cyclic character of being identified signals and the necessity of cyclic synchronization before the identification procedure This complicates technical realization essentially as well as does requirements to computational resources of known algorithm. This article offers improved algorithm for identification of code signals transferred via rail chains in the process of train traffic which doesn’t demand cycle synchronization. For to solve cycle synchronization problem it’s been offered to accomplish code signal identification by Fourier amplitude spectrum of its preselected envelope. Such settlement has become possible on account of invariance of Fourier amplitude spectrum of code signal envelope relatively code signal shift in the time domain on random number of digital readings. As a machinal training method, the article considers artificial neural network with simplified, compared with the previous analogues, architecture. While identification, three-layer neural network with full connections between layers is engaged. Also, the work investigates limitations of suggested method of machinal identification which are conditioned by refuse from phase spectrum of envelope of being processed code signal. It’s been demonstrated in the article the act of improved method of machinal identification on real signals fixed in being exploited rail lines. The obtained results testify the adequacy of the suggested methodology for the identification of signals of automatic locomotive signaling of systems for train traffic interval regulation.

A simple method for comparing peripheral and central color vision by means of two smartphones.

Information on peripheral color perception is far from sufficient, since it has predominantly been obtained using small stimuli, limited ranges of eccentricities, and sophisticated experimental conditions. Our goal was to consider the possibility of facilitating technical realization of the classical method of asymmetric color matching (ACM) developed by Moreland and Cruz (1959) for assessing appearance of color stimuli in the peripheral visual field (VF). We adopted the ACM method by employing two smartphones to implement matching procedure at various eccentricities. Although smartphones were successfully employed in vision studies, we are aware that some photometric parameters of smartphone displays are not sufficiently precise to ensure accurate color matching in foveal vision; moreover, certain technical characteristics of commercially available devices are variable. In the present study we provided evidence that, despite these shortages, smartphones can be applied for general and wide investigations of the peripheral vision. In our experiments, the smartphones were mounted on a mechanical perimeter to simultaneously present colored stimuli foveally and peripherally. Trying to reduce essential discomfort and fatigue experienced by most observers in peripheral vision studies, we did not apply bite bars, pupil dilatation, and Maxwellian view. The ACM measurements were performed without prior training of observers and in a wide range of eccentricities, varying between 0 and 95°. The results were presented in the HSV (hue, saturation, value) color space coordinates as a function of eccentricity and stimulus luminance. We demonstrated that our easy-to-conduct method provided a convenient means to investigate color appearance in the peripheral vision and to assess inter-individual differences.