bluuebunny/crossref_metadata_2025 huggingface dataset:
Wireless‐powered CR‐IoT with ambient backscattering: a new transmission mode
Authors: Sun Mengwei , Ding Yuan , Goussetis George
Published: February 2021

In this study, a new hybrid secondary transmitter (ST) mode is proposed for cognitive radio Internet of Things (CR‐IoT) networks with energy harvesting (EH) and ambient backscatter (AmBack) communication capabilities. The authors firstly describe the proposed hybrid mode with wireless‐powered ST. The ST, consisting of EH, Amback, and conventional active transmission modules, adapts itself under different primary user operation states, i.e. active or idle. The overall throughput of the secondary system is formulated and the system settings for achieving optimal performance are derived and validated through numerical simulations.
Joint communication and radar sensing in 5G mobile network by compressive sensing
Authors: Rahman Md Lushanur , Zhang J. Andrew , Huang Xiaojing , Guo Y. Jay , Lu Zhiping
Published: February 2021

Radio sensing can be integrated with communication in what the authors call future perceptive mobile networks. Due to the complicated signal structure, it is challenging to estimate sensing parameters such as delay, angle of arrival, and Doppler when joint communication and radar/radio sensing is applied in perceptive mobile networks. Radio sensing with signals compatible with a fifth‐generation (5G) new radio standard using one‐dimension (1D) to 3D compressive sensing (CS) techniques under 5G channel conditions is studied. In the case of 1D–3D CS techniques, they formulate the parameter estimation as a sparse signal recovery problem. These algorithms demonstrate respective advantages, but also show shortcomings in dealing with clustered channels. To effectively exploit the cluster structure in multipath channels, they also propose a 2D cluster Kronecker CS algorithm for significantly improved sensing parameter estimation via introducing a prior probability distribution. Simulation results are provided and they focus the respective advantages and disadvantages of these techniques that validate the effectiveness of the proposed algorithms.
Deep network approach with stacked sparse autoencoders in detection of DDoS attacks on SDN‐based VANET
Authors: Polat Huseyin , Turkoglu Muammer , Polat Onur
Published: February 2021

Software‐defined network (SDN)‐based vehicular ad hoc network (VANET) is an outstanding technology for smart transportation as it increases traffic safety, efficiency, comfort, and manageability. However, despite all its benefits and good performance, SDN‐based VANET is vulnerable to attack threats such as distributed denial of service (DDoS). When SDN‐based VANET systems are exposed to DDoS attacks, this may affect traffic safety, causing traffic accidents and deaths. Therefore, the relevant security threats need to be addressed before integrating the SDN‐based VANETs into smart transportation systems. In this study, the stacked sparse autoencoder (SSAE) + Softmax classifier deep network model is proposed to detect DDoS attacks targeting SDN‐based VANETs. The features in the dataset obtained from the SDN‐based VANET were reduced dimensionally utilising SSAE, and the most significant features were obtained. Then, these features were used as input into the Softmax classifier. According to the experimental results, the best accuracy scores were calculated as 96.9% using the four‐layer SSAE + Softmax classifier deep network model proposed. When compared, the results demonstrate the SSAE + Softmax classifier deep network model proposed can obtain better results in the classification of DDoS attacks and is more successful than the other machine learning classifiers.
Application of GSVD‐based precoding in MIMO‐NOMA relaying systems
Authors: Rao Chenguang , Ding Zhiguo , Dai Xuchu
Published: February 2021

In this study, a simple two‐user multiple‐input multiple‐output (MIMO) relaying scenario is considered. To efficiently exploit the spectrum resources, a generalised singular value decomposition (GSVD) based precoding scheme with non‐orthogonal multiple access (NOMA) is proposed, which converts the multiple channels into several parallel single channels. The performance of the proposed GSVD‐MIMO relaying scheme is evaluated by using the distribution characteristics of squared generalised singular values of two users' channel matrices and the eigenvalues of the relay's channel matrix to obtain the expressions of the average data rate and outage probabilities. Both the asymptotic case and a practical scenario with nodes equipped with finite numbers of antennas are analysed because the distribution characteristics of squared generalised singular values in the two cases are different. Two special cases, single‐input multiple‐output and multiple‐input single‐output are considered. Simulation experiments are carried out to verify the effectiveness and accuracy of the obtained analytical results.
Two‐stage visible watermark removal architecture based on deep learning
Authors: Jiang Pei , He Shiwen , Yu Hufei , Zhang Yaoxue
Published: February 2021

With the rapid development of the Internet, watermarks are widely used in images to protect copyright. This implies that the robustness of watermark is very important. In recent years, there have been some studies to evaluate watermark performance by removing the watermark. Among them, some methods need to mark the watermark position in advance, and some require multiple images with the same watermark. Moreover, when the colour of thewatermark is similar to that of the background, the existing methods can hardly remove the watermark from the watermarked image. In the proposed work, the authors presented a watermark removal structure consisting of watermark extraction and image inpainting to address the aforementioned issues. In particular, the extraction network is used to extract the watermark in the watermarked image, and the inpainting network is used to inpainting image for a better watermark removal image, respectively. Finally, the authors train and test the developed network architecture by constructing two data sets, i.e. white watermarked image data set (WW‐data set) and colour watermarked image data set (CW‐data set). The proposed method not only has better performance on the WW‐data set than the current latest methods (on the CW‐data set, other methods have almost failed) but also effectively removes the watermarks.
Multi agent‐based strategy protecting the loop‐based micro‐grid via intelligent electronic device‐assisted relays
Authors: Karimi Hamed , Fani Bahador , Shahgholian Ghazanfar
Published: February 2021

Penetrating distributed generation units into the radial distribution networks has been making the protection schemes become ever so complex. The microgrid modes of operation have also increased this complexity. Moreover, the ‘loop‐based microgrid’ concept has made it extremely difficult or even impossible to utilise the available radial protection schemes. Although redesigning a new protection structure solves the problem, there should be an affordable way for surviving today's protection systems; accordingly, this study equips the ordinary overcurrent relays with intelligent electronic devices to act as an agent within a multi‐agent framework. Given these devices are equipped with an efficient communication infrastructure for industrial applications, named IEC 61850 standard, the proposed approach uses a communication‐based strategy, named token, to securely protect the system without any conflict in relays’ operation. The simulation results prove the effectiveness of the proposed method for any DG's penetration, network configuration and fault location. This kind of flexible strategies can affordably differ the expensive protection system replacement in the future revolutionary network upgrades.
Analysis and tuning methodology of FAPI controllers for maximising the share of grid‐connected wind generations
Authors: Rakhshani Elyas , Perilla Arcadio , Veerakumar Nidarshan , Ahmad Zameer , Rueda Torres Jose , van der Meijden Mart , Palensky Peter
Published: February 2021

In this study, a novel methodology is proposed for sensitivity‐based tuning and analysis of derivative‐based fast active power injection (FAPI) controllers in type‐4 wind turbine units integrated into a low‐inertia power system. The FAPI controller is attached to a power electronic interfaced generation (PEIG) represented by a generic model of wind turbines type 4. It consists of a combination of droop and derivative controllers, which is dependent on the measurement of the frequency. The tuning methodology performs parametric sensitivity to search for the most suitable set of parameters of the attached FAPI that minimises the maximum frequency deviation in the containment period. The FAPI is adjusted to safeguard system stability when increasing the share of PEIG. Since the input signal of the FAPI is the measured frequency, the impact of different values and parameter settings of the phase‐locked loop used for the FAPI controller is also investigated. Detailed validation with a full‐scaled wind power converter is also provided with a real‐time digital simulator testbed. Obtained simulation results using a three‐area test system, identify the maximum achievable degree of increase in the share of wind power when a proper combination of wind park locations considering their suggested settings for inertia emulation.
Novel double‐layer DC/AC railway traction power supply system with renewable integration
Authors: Li Yongfei , Li Kang , Zhang Li , Li Yong
Published: February 2021

Back‐to‐back converter based railway traction power supply system (TPSS) can eliminate neutral sections in the traction side and improve power quality in the grid side, but it still has some drawbacks such as low reliability, difficulty in accepting large‐capacity renewable energy, and power mismatches. In this study, a double‐layer DC/AC TPSS with renewable integration is proposed to address these challenges and to improve system performance. The proposed topology breaks the limit of back‐to‐back structure and enables more flexible free energy flow. A top‐down system design method is proposed in this study. Firstly, the characteristics of the proposed TPSS for integration with renewable power are described and compared with the traditional back‐to‐back topology. Secondly, a DC droop controller and a AC droop controller are designed for DC layer grid and AC layer grid, respectively, to control the power flow in each layer. The traditional AC droop control is based on the inductive transmission impedance, but the resistance of traction transmission line cannot be ignored. Thus, a modified droop control strategy with the consideration of line resistance is also proposed in this study. Subsequently, the voltage control strategy for the single modular multilevel converter is designed to track the reference signal from the upper droop controller. Finally, a general double‐layer DC/AC TPSS is designed from bottom to top, and the simulation results confirm that the proposed TPSS with renewable integration is capable of delivering desirable performance.
Virtual inertia provision through data centre and electric vehicle for ancillary services support in microgrid
Authors: Elizabeth Michael Neethu , Hasan Shazia , Mishra Sukumar
Published: February 2021

The proposal focuses on the role of data centres (DCs) and electric vehicle (EV) energy storage systems (ESSs) for frequency regulation and it provides a new opportunity for different resources to participate in the power sector. Frequency fluctuations are introduced with the emergence of inverter‐dominated renewable energy sources (RESs) as it does not provide rotational inertia to the grid, such as synchronous generators. In this study, the virtual synchronous generator (VSG) controlled inverter compensates for the lack of inertia. Particularly, this research work analyses the involvement of DC and EV batteries as ESSs in designing an integrated technical virtual power plant (VPP) to support frequency variations using the VSG concept. Microgrid (MG) simulations are performed in MATLAB/ Simulink platform. Case studies are carried out to validate the grid export and grid import performance of the model by using variations in the load and the solar irradiance of the MG. It is verified that bidirectional power flow takes place between the proposed VPP components and the grid that enables the grid with high penetration of RESs. The work provides a conceptual framework for future contributions towards the smarter usage of assets such as ESS and a greener future.
Power to air transportation via hydrogen
Authors: Soroudi Alireza , Jafari Soheil
Published: February 2021

This study proposes a framework to analyse the concept of power to hydrogen (P2H) for fuelling the next generation of aircraft. The impact of introducing new P2H loads is investigated from different aspects namely, cost, carbon emission, and wind curtailment. The newly introduced electric load is calculated based on the idea of replacing the busiest international flight route in the Europe, Dublin‐London Heathrow, by hydrogen fuel‐powered aircraft as a high potential candidate for the next generation of air travel systems to cope with the ambitious targets set in Europe Flight Path 2050 by the Advisory Council for Aeronautics Research in Europe. The simulation is performed on a representative Irish transmission network to demonstrate the effectiveness of the proposed solution.
Fundamental switched MW‐size multilevel converter for large‐scale solar PV plant
Authors: Karmakar Subir , Mishra Nidhi , Yadav Shivam Kumar , Singh Bhim
Published: February 2021

The requirement of high power (MW‐size) power conditioning unit (PCU) has increased to minimise the plant balance of system cost due to a continuous increase in solar photovoltaic (PV) plant capacity. Traditionally used high‐frequency pulse‐width modulated two/three‐level PCUs have high device switching losses and lower conversion efficiency and are not suitable for high power PCU application as high switching losses lead to high heat generation within the converter, which is very difficult to manage, and lower conversion efficiency leads to less revenue realisation. In the present work, fundamental switching selective harmonic elimination (SHE) modulated 11‐level cascaded H‐bridge voltage source converter is utilised for high power MW‐size PCU application, as it has lower switching losses, higher conversion efficiency, and higher AC/DC voltage ratio. The PV plant configuration for a 40 MW (AC) capacity is developed in the MATLAB/Simulink environment and implemented in real‐time simulator OPAL‐RT to validate the design and control. Harmonics, steady‐state, and dynamic performances are demonstrated at constant and changing solar irradiance levels. The converter conduction and switching losses and conversion efficiency at different loading conditions are presented. The converter control with the capacitor voltage balancing method for fundamental switched SHE is presented in detail.
The central parsec of NGC 3783: a rotating broad emission line region, asymmetric hot dust structure, and compact coronal line region
Authors:   GRAVITY Collaboration, Amorim A. , Bauböck M. , Brandner W. , Bolzer M. , Clénet Y. , Davies R. , de Zeeuw P. T. , Dexter J. , Drescher A. , Eckart A. , Eisenhauer F. , Förster Schreiber N. M. , Gao F. , Garcia P. J. V. , Genzel R. , Gillessen S. , Gratadour D. , Hönig S. , Kaltenbrunner D. , Kishimoto M. , Lacour S. , Lutz D. , Millour F. , Netzer H. , Ott T. , Paumard T. , Perraut K. , Perrin G. , Peterson B. M. , Petrucci P. O. , Pfuhl O. , Prieto M. A. , Rouan D. , Sanchez-Bermudez J. , Shangguan J. , Shimizu T. , Schartmann M. , Stadler J. , Sternberg A. , Straub O. , Straubmeier C. , Sturm E. , Tacconi L. J. , Tristram K. R. W. , Vermot P. , von Fellenberg S. , Waisberg I. , Widmann F. , Woillez J.
Published: February 2021

Using VLTI/GRAVITY and SINFONI data, we investigate the subparsec gas and dust structure around the nearby type 1 active galactic nucleus (AGN) hosted by NGC 3783. The K-band coverage of GRAVITY uniquely allows simultaneous analysis of the size and kinematics of the broad line region (BLR), the size and structure of the near-infrared(near-IR)-continuum-emitting hot dust, and the size of the coronal line region (CLR). We find the BLR, probed through broad Brγ emission, to be well described by a rotating, thick disc with a radial distribution of clouds peaking in the inner region. In our BLR model, the physical mean radius of 16 light-days is nearly twice the ten-day time-lag that would be measured, which closely matches the ten-day time-lag that has been measured by reverberation mapping. We measure a hot dust full-width at half-maximum (FWHM) size of 0.74 mas (0.14 pc) and further reconstruct an image of the hot dust, which reveals a faint (5% of the total flux) offset cloud that we interpret as an accreting or outflowing cloud heated by the central AGN. Finally, we directly measure the FWHM size of the nuclear CLR as traced by the [Ca VIII] and narrow Brγ line. We find a FWHM size of 2.2 mas (0.4 pc), fully in line with the expectation of the CLR located between the BLR and narrow line region. Combining all of these measurements together with larger scale near-IR integral field unit and mid-IR interferometry data, we are able to comprehensively map the structure and dynamics of gas and dust from 0.01 to 100 pc.
Signatures of ubiquitous magnetic reconnection in the deep atmosphere of sunspot penumbrae
Authors: Rouppe van der Voort Luc H. M. , Joshi Jayant , Henriques Vasco M. J. , Bose Souvik
Published: February 2021

Context. Ellerman bombs are regions with enhanced Balmer line wing emission and mark magnetic reconnection in the deep solar atmosphere in active regions and the quiet Sun. They are often found in regions where opposite magnetic polarities are in close proximity. Recent high-resolution observations suggest that Ellerman bombs are more prevalent than previously thought.

Aims. We aim to determine the occurrence of Ellerman bombs in the penumbra of sunspots.

Methods. We analyzed high spatial resolution observations of sunspots in the Balmer Hα and Hβ lines as well as auxiliary continuum channels obtained with the Swedish 1-m Solar Telescope and applied the k-means clustering technique to systematically detect and characterize Ellerman Bombs.

Results. Features with all the defining characteristics of Ellerman bombs are found in large numbers over the entire penumbra. The true prevalence of these events is only fully appreciated in the Hβ line due to the highest spatial resolution and lower chromospheric opacity. We find that the penumbra hosts some of the highest Ellerman bomb densities, surpassed only by the moat in the immediate surroundings of the sunspot. Some penumbral Ellerman bombs show flame morphology and rapid dynamical evolution. Many penumbral Ellerman bombs are fast moving with typical speed of 3.7 km s−1 and sometimes more than 10 km s−1. Many penumbral Ellerman bombs migrate from the inner to the outer penumbra over hundreds of km, and some continue moving beyond the outer penumbral boundary into the moat. Many penumbral Ellerman bombs are found in the vicinity of regions with opposite magnetic polarity.

Conclusions. We conclude that reconnection is a near continuous process in the low atmosphere of the penumbra of sunspots that manifest in the form of penumbral Ellerman bombs. These are so prevalent that they may be a major sink of sunspot magnetic energy.
Thermodynamic analysis of a Carbon Carrier Cycle (CCC) for low temperature heat recovery
Authors: Micheli Diego , Reini Mauro , Taccani Rodolfo
Published: February 2021

The aim of the paper is to study the thermodynamic behavior of a non-conventional power cycle, named Carbon Carrier Cycle (CCC), which is expected to obtain interesting performance with low temperature heat source. The CCC may be regarded as derived from an absorption machine, where an expander replaces the condenser, the throttling valve and the evaporator. The working fluid is a mixture of CO2 and a proper absorber. In the paper, the thermodynamic model of this kind of cycles is described, and the results obtained considering Acetone as the absorber are discussed. A first performance comparison is then conducted with a more conventional Organic Rankine Cycle (ORC).
On the potential yield of wind turbines on high-rise buildings
Authors: Vita Giulio , Salvadori Simone , Sarkić-Glumac Anina , Misul Daniela Anna
Published: February 2021

Urban wind energy has intrigued some investments and applications over the last decade. However, most applications have been unsuccessful, in many cases leaving behind non-rotating wind turbines in the built environment. Research on urban wind energy has also lacked in providing a reliable description of the local flow features small wind turbines are placed in, and the positioning strategy is mostly based on empiricism. This study uses data from a wind tunnel test on the flow pattern above the roof of high-rise buildings to estimate the potential yield of small wind turbines installed in various configurations. The data are collected at a height of 12 m above the flat roof under various wind directions. The capacity factor of a medium-size horizontal axis wind turbine is calculated using power curve data available from the literature. The local wind resource is calculated using the mean wind speed as measured with hot-wire anemometry. The annual energy production of the various configurations is calculated using the climate data available for Firenze (IT) and the orientation of the building with respect to main winds. A rather large variability in the power output of the roof-farm was found for the chosen configuration.
Energy recovery from biowaste: influence of hydraulic retention time on biogas production in dry-anaerobic digestion
Authors: Rossi Elena , Pecorini Isabella , Iannelli Renato
Published: February 2021

The hydraulic retention time (HRT) is a key parameter in dry-anaerobic digestion to set during the reactor configuration in order to achieve the optimal biogas production. For this reason, the study compared the results of two experimental tests operating with an HRT of 23 and 14 days. During the tests, the feedstock was organic fraction of municipal solid waste with a solid content of 33% and the digester was a pilot-scale plug-flow reactor operating in thermophilic condition. The highest specific biogas production of 311.91 Nlbiogas kg-1 d-1 was achieved when the HRT was set to 23 days. On the contrary, the highest methane production rate of 1.43 NlCH4 l-1 d-1 was achieved for an HRT of 14 days. In addition, the volatile solids removal (49.15% on average) and the energy content o(4.8 MJ kg-1 on average) were higher for HRT 23 days than for HRT14 days. The results indicated that in dry-anaerobic digestion of organic fraction of municipal solid waste, 23 days is a suitable HRT for energy recovery.
Renewables exploitation via hydrogen production in gas turbine test facilities: the ZEHTC Project
Authors: Ancona Maria Alessandra , Bianchi Michele , Branchini Lisa , Catena Francesco , De Pascale Andrea , Melino Francesco , Peretto Antonio
Published: February 2021

In order to pursue the goals of de-carbonization and renewable sources exploitation, an efficient, cost-effective and environmental friendly employment of energy systems is mandatory. In this context, the ERA-Net funded Project ZEHTC (Zero Emission Hydrogen Turbine Center) has been developed, aimed at the realization of a pilot plant consisting in the world first gas turbine test facility making use of the power produced during turbine tests – along with renewables (solar in particular) – for hydrogen production and batteries storage. The produced hydrogen will be locally used to run the gas turbine, thus reducing its environmental impact. The aim of this paper is to present the results of the first steps of the project, consisting in the definition of an optimized grid and in the development of a calculation model for the optimal energy systems design. To this respect, the typology of energy systems to be included into the grid (in addition to the current set-up of the existing turbine test center) will be presented. In addition, the mathematical models specifically developed for each component, as well as the developed operational logic of the entire grid, will be presented and discussed in order to set the optimal size of each systems.
Clean fuels synthesis from green hydrogen: a techno-economic comparative analysis
Authors: Bellotti Daria , Rivarolo Massimo , Magistri Loredana
Published: February 2021

In this paper, two different power-to-fuel solutions for sustainable fuel synthesis are investigated from the energetic, environmental, and economic standpoints. Both the solutions consider a pressurized PEM electrolysis section, fed by renewable sources, where high purity green Hydrogen is produced. Then, two separate processes are investigated for the synthesis of two distinct chemicals. In the first case, the hydrogen is mixed with CO2, sequestered by an industrial plant, and captured a carbon capture system (CCS): the two gases are sent to a pressurized reactor for methanol synthesis. In the second case, the hydrogen is mixed with N2, obtained from an industrial air separation unit (ASU), and sent to a reactor for ammonia synthesis. Both the synthesis processes are performed at high pressures and temperatures, thus a thermodynamic analysis is mandatory in order to calculate the overall efficiencies. In both cases, the power to fuel plants are investigated also in economic terms. Methanol synthesis presents a slightly higher efficiency compared to ammonia, while the two solutions are very similar from the economic standpoint. The sale of the co-produced oxygen allows for an improvement in economic terms for both cases and can be a key point in order to reach economic sustainability, together with the expected reduction in PEM electrolysers capital cost.
A guideline to link the off-design performance of a micro-gas turbine to a heavy-duty gas turbine in a test rig that aim to investigate flexibility of GTCC
Authors: Reboli Tommaso , Rossi Iacopo , Traverso Alberto , Torelli Giorgio
Published: February 2021

In the era of coal power station phase-out, natural gas fired combined cycle will drive the energy transition towards sustainable power generation. In a panorama of strong requirement for grid flexibility and non-dispatchable renewable penetration, the survival of a thermal power plant is strictly linked with operating successfully in compensating the renewable fluctuating production through flexible generation. The Italian case is taken as reference, considering that energy transition and renewable energy penetration may have similar effects also in different countries. In this direction, a test rig to investigate gas turbine compressor inlet conditioning techniques has been developed at the Tirreno Power laboratory of the University of Genoa, Italy. This is based on a Turbec T100 micro gas turbine (or microturbine), a Mayekawa heat pump and a phase-change material energy storage. The whole test-rig is virtually scaled up, through a cyber-physical system, to emulate a real 400MW combined cycle, with the heat pump governing the inlet conditions at the compressor. The microturbine is therefore used as the physical feedback for the system, whilst the steam bottoming cycle is simulated in real-time according to microturbine operation. The scope is to present the test rig and the procedure adopted to virtually scaleup a microturbine to a heavy-duty GT. the advantage of using microturbine for testing combined cycle flexibility options lays also on the possibility to make accelerated tests and to simulate multiple situations in compressed time windows.
Complex energy networks: energy-ecological efficiency based evaluations towards the sustainability in energy sector
Authors: Ancona Maria Alessandra , Bianchi Michele , Branchini Lisa , De Pascale Andrea , Melino Francesco , Peretto Antonio
Published: February 2021

In the last years, international programs in diverse sectors and national frameworks have been driven by the need of a sustainable growth, in a green economy perspective. In order to reduce the energy losses/dissipations, as well as the fossil fuels employment and related pollutant emissions, indeed, the spread of combined heat and power units and/or renewable sources generators is promoted into both the electrical grids and the thermal networks but are often in conflict with the economic aspects. In this context, the optimal management of complex energy networks – including, in particular, smart district heating – may lead to the achievement of important goals from the environmental and sustainability viewpoints. The aim of this paper is to develop a preliminary methodology for the complete evaluation of complex energy networks, considering energy, economic and environmental aspects. With this purpose, a case study consisting in a network for the fulfillment of electrical and thermal needs of the connected users will be analyzed, considering different scenarios in terms of energy generation mix and operation and applying different optimization software. In addition, the carried out evaluations will allow to set the basis for the discussion about the future of energy policies and possible incentives towards the sustainable development of the energy sector.
Strategic Alliances in the Electromobility Sector
Authors: Mule Letizia , Belingheri Paola , Bonaccorsi Andrea
Published: February 2021

Since the late 2000s, the transition from a fossil fuel-based system to the fully renewable system has begun. This period, known as an “Era of Ferment”, is characterized by high technical and economic uncertainty and it’s leading the automotive industry towards a paradigm shift: developing new car technologies, creating charging infrastructure needs and shaking up the supply chain structure. In light of ecosystem theory and the importance of alliances in the quest to develop an electric vehicle market, this paper analyses the electromobility ecosystem, tracking its lifecycle and investigating vertical and horizontal alliances between the main actors over time, including original equipment manufacturers, traditional suppliers, battery suppliers, and charging infrastructure providers. We analyzed an original longitudinal dataset composed of 281 alliances in the electric passenger vehicles market, initiated between 2000 and 2015. Through the study of the network of alliances, we describe the Electric Vehicle ecosystem’s evolution, examining the entry time of incumbents, suppliers and complementors, the role of actors in the ecosystem and their previous industry sector, the key knowledge they possess and technological areas in which they operate, and the nations involved. Key network measures also provide insights into power and connectedness of different actors, highlighting a creative accumulation strategy of the incumbents.
Waste food reduction as a way to reduce resources and energy consumption in the Italian industrial sector: an IO-LCA analysis
Authors: Bartocci Pietro , Yang Qing , Zhou Hewen , Chen Bin , Fantozzi Francesco
Published: February 2021

Food production involves both agricultural and industrial activities which consume several resources among which: water, energy, land, minerals and chemicals. The efficiency in the use of the resources depends on the type of food which is produced and the adopted processes. In any case if food is discarded or lost at any step of the supply chain this represents a waste of energy and resources. For this reason, the LIFE project irexfo, coordinated by the University of Perugia has proposed a way to promote a business model aiming at both: the reduction of food losses and also the reuse of the not comestible food waste in biogas plants. The model has been tested in Umbria as a pilot region and in this study the results obtained are scaled up to a national level and applied to the Italian IO database reported in the EXIOBASE, to evaluate which could be the benefits of the application of the irexfo business model to the whole Italian agroindustry sector and also the interrelations between this sector and the Italian energy sector. The analysis is performed using SimaPro software 9.0, results are compared with those of similar studies which have been performed at European level. This is the first study of this kind focused on Italy.
An innovative tool for the evaluation and comparison of different fuels and technologies onboard ships
Authors: Rattazzi Diego , Rivarolo Massimo , Massardo Aristide F.
Published: February 2021

The paper focuses on the analysis of innovative energy systems onboard ships with the aim to evaluate, in a preliminary stage, which can be the most promising solution depending on the considered application. For this purpose, the dedicated tool HELM developed by the authors’ research group is employed. The tool uses maps reporting the main indicators (weight, volume, costs and emissions) for each component in relation to the installed power and the operational hours required (given by the user as an input), then it compares the results providing the best solution depending on the considered application. The maps have been built from a database developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines), fuels (hydrogen, natural gas, diesel, methanol) and related storage technologies. The main strong point of HELM resides in its flexibility: it can be used for different typologies and sizes of ships (e.g. ferry boat, cruises, yachts); moreover, the database can be easily updated with more technologies. In this work, the focus is particularly on hydrogen application with PEM Fuel Cells and the use of innovative fuels (methanol, ammonia) in Internal Combustion Engines. Analysing different applications, it will be highlighted how the specific characteristics and priorities of the application affect the results of the best solutions. Furthermore, considering the regulation roadmap for the next years in the maritime context, promising technologies are highlighted also for future scenarios.
Technological options towards a carbon neutral town in central Italy
Authors: Bartolini Andrea , Salvi Danilo , Pelagalli Leonardo , Caresana Flavio , Comodi Gabriele
Published: February 2021

The paradigm of highly integrated cross sector energy systems grants several opportunities for welcoming high shares of renewable energy sources in meeting the energy demands of current urban districts. A key asset towards such challenge lies in the progressive deployment of more distributed energy systems, achieving configurations tailored to the needs of the local communities lying in their physical proximities.

This study analyses the case study of a small town situated in central Italy, which energy supply already features a set of distributed and cross-sector energy resources such as a district heating network fed by a 1.2 MWe natural gas engine and more than 30 MWp of non-controllable renewables.

The city energy systems are modelled in the analysis tool EnergyPLAN in order to analyse the technical feasibility of introducing different technological options aimed at reducing the polluting emissions generated in meeting different energy related needs of the district.
A revised Tesla Turbine concept for 2-phase applications
Authors: Talluri L. , Niknam P. , Copeta A. , Amato M. , Iora P. , Uberti S. , Invernizzi C. , Di Marcoberardino G. , Pacini L. , Manfrida G. , Fiaschi D.
Published: February 2021

The Tesla turbine is an original expander working on the principle of torque transmission by wall shear stress. The principle – demonstrated for air expanders at lab scale has some attractive features when applied to two-phase expanders: it is suitable for handling limited flow rates (as is the case for machines in the range from 500W to 5 kW), it can be developed to a reasonable size (rotor of 0.1 to 0.25 m diameters), with acceptable rotational speeds (which range from 500 to 10000 rpm). The original concept was revisited, designing it for two-phase operation and considering not only the rotor configuration but the whole machine. The flow model was developed using complete real fluid assumptions including several new concepts such as bladed channels for the stator, labyrinth seals, and a rotating diffuser. Preliminary design sketches are presented, and results discussed and evaluated.
Enhancement of both optical and catalytic activity of copper-decorated porous silicon micro-particles
Authors: Hamdi Abderrahmane , Amri Chohdi , Ouertani Rachid , Dogheche Elhadj , Ezzaouia Hatem
Published: February 2021

To the best of our knowledge, this study is the first to investigate the effect of chemical vapour etching (CVE) combined with copper decoration on both the optical and catalytic activities of silicon micro-particles (SiμPs). After exposure to acid vapours emanating from a hot solution of hydrogen fluoride/nitric acid (HF/HNO3), scanning electron microscope images of the treated powder show the formation of a porous, sponge-like structure on the sidewalls of SiμPs. Fourier transmission infra-red analysis shows the appearance of hydride bonds related to the formation of the porous structure. X-ray diffraction measurements and Raman spectroscopy show the good crystallinity of the samples. The strong photoluminescence properties of the obtained porous SiμPs (pSiμPs) reveal that the vapour etching process generated silicon nanocrystals within these particles. In this work, we have investigated the catalytic activity of copper nanoparticles (CuNPs) loaded on the surface of pSiμPs, in order to reduce the toxic compound 4-nitrophenol to 4-aminophenol. The results show excellent catalytic performance in very short times (less than 1 min).
Optimal government support policy towards technology development considering the challenges of conflict of interests, ethical and structural problems
Authors: Bagheri Nasrabadi Mahdi , Jassbi Abdullah , Bonyadi Naeini Ali , Shavvalpour Saeid
Published: February 2021

One of the main ways of economic development is technological innovation development. The support provided by the government and the policies adopted for technology developments are important issues in the context of technology and innovation policymaking. On the other hand, the structural issues in some countries, especially in Iran, as well as the conflict of interests and ethical problems, are of crucial importance in large-scale technology development projects. The present paper addresses governmental policies and support and the underpinning parameters given the points mentioned about the economic and technological development of Iran. In this study, we first interviewed some experts, and the results were employed as inputs of the quantitative model. The important parameters influencing the determination of governmental support and policy type were also addressed. The long-term behavior of the public and private sectors as two key players were analyzed by the evolutionary game theory and their strategies were solved by replicative dynamic equations. Finally, a numerical study was conducted for a real case in Iran to better understand the features of the game model in real conditions. The results of the case study show that the main approach of the government should be legal monitoring although the minimum incentive policies and supports should also be in place. The sensitivity analysis of some major parameters reveals that the main factor in project implementation is to consider the income and costs of the private sector. The governmental policy should be based on preparing incentive mechanisms at an appropriate level and then precise legal monitoring, which will lead to technology development with the cooperation of the parties, minimum ethical problems, and the minimization of the impact of structural problems, including sanctions.
Older patients with proximal femur fractures and SARS-CoV-2 infection – An observational study
Authors: Burahee Abdus S , Barry Veronica E , Sutcliffe Robert P , Mahroof Sabreena
Published: February 2021

Background: Older patients are at increased risk of severe COVID-19 infection and associated mortality. There are limited data evaluating the outcome of older patients with hip fractures treated during the COVID-19 pandemic, and it has been suggested that these patients should be treated non-operatively due to high mortality risk. The aim of this study was to report the outcomes of COVID-19 infected hip fracture patients treated at a single centre. Methods: This was a retrospective cohort study. Data were collected from February 2020 (after the first confirmed COVID-19 infected patient was reported in the Midlands region of the UK). All patients admitted to the hospital with femoral neck fractures were included. Patient demographics, comorbidity, COVID-19 status, and short-term clinical outcomes were obtained by review of electronic medical records. The outcomes of COVID-19 infected patients were compared with non-COVID-19 patients treated during the study period. Results: Twenty-nine patients were included (mean age of 80 years), of whom 14 (48%) were tested positive for COVID-19 infection in the postoperative period. Overall, 26 patients (90%) underwent surgical treatment. COVID-19 infected patients had significantly higher Charlson comorbidity scores compared to the control group (5 vs. 4; p = 0.047). Only 5 COVID-19 infected patients (36%) required supplemental oxygen therapy in the postoperative period, and no patients required respiratory or other organ support. The 30-day mortality rate in COVID-19 patients was 14% compared to 0% in the negative controls (p = 0.22). Interpretation: COVID-19 infection did not increase the mortality rate of older patients undergoing surgery for hip fractures during the pandemic. The authors recommend careful assessment of patient fitness and prompt surgical treatment. In addition, it was noted that nearly all admissions were either given large boluses of Vitamin D or were on maintenance supplementation, which may have affected the severity of the response to COVID-19 infections.
Klinische Anatomie des Plexus lumbosacralis
Authors: Peuker Elmar T.
Published: February 2021

Spinalnerven definieren den Versorgungsbereich des jeweiligen Rückenmarksegments. Die Kenntnis der im Rahmen der Entwicklung teilweise stark divergierenden Segmentanteile ist u. a. für die Diagnostik und Therapie schmerzhafter Störungen wichtig. Dabei spielt insbesondere die Differenzierung radikulärer Störungen von Störungen durch Affektion peripherer Nerven eine bedeutende Rolle. Letztere resultieren häufig aus einer Einengungssymptomatik, die unterschiedliche Ursachen haben kann und v. a. auch bei Fehlhaltungen und muskulären Dysbalancen auftritt. Für eine effektive Therapie muss die resultierende Symptomatik eindeutig eingeordnet werden.
Rheumatologe per Ritterschlag: Die Entwicklung der Rheumatologie in Mecklenburg-Vorpommern
Authors: Keysser Martin
Published: February 2021

Der Weg zum Facharzt für Innere Medizin/Rheumatologie ist heute
eindeutig definiert. Aktuelle Verordnungen der Bundesärztekammer und der
Landesärztekammern legen fest, welche Voraussetzungen ein weiterbildendes
Zentrum aufweisen muss und welche Schritte AssistenzärtInnen absolvieren
müssen, um zur rheumatologischen Facharztprüfung zugelassen zu
werden. Eine wichtige Rolle bei der Weiterbildung spielen heute die regionalen
kooperierenden Rheumazentren. Auch diese müssen klar bezeichnete
Qualitätsanforderungen erfüllen, um von der Deutschen Gesellschaft
für Rheumatologie das Qualitätszertifikat „DGRh
Rheumazentrum“ zu erhalten. Diese begrüßenswerten
Festlegungen, welche die Behandlungsqualität der Rheumapatienten sichern,
sind das Ergebnis einer langen Entwicklung. Anhand meines eigenen beruflichen Weges
möchte ich darlegen, wie der Weg zum Rheumatologen in der Vergangenheit
aussah.
Antivirale Wirkungen eines Thymianextrakts – ein Update
Authors: Wegener Tankred
Published: February 2021

Die Anwendung von Zubereitungen aus Thymiankraut bei Erkältungskrankheiten mit Husten kann – beruhend auf experimentellen Untersuchungen – mit spasmolytischen, expektorierenden, antibakteriellen und evtl. auch mit antiinflammatorischen Wirkungen in Zusammenhang gebracht werden. Neuere Hinweise auf antivirale Wirkungen eines Thymianextraktes, hier auf Rhino- und Influenzaviren, die frühere Daten und etablierte Verwendungen bestätigen, geben genügend Anlass, sich auch diesbezüglich das klinische Potenzial des Thymiankrautextraktes vertiefend anzuschauen.
GHB
Authors: Scherbaum Norbert
Published: February 2021

Abb. 1 zeigt die Strukturformel, die Anwendungsarten
und die handelsüblichen Formen von GHB.
Screening of febrile cows using a small handheld infrared thermography device
Authors: Bleul Ulrich , Hässig Michael , Kluser Fabienne
Published: February 2021

Objective As dairy herds increase in size, close monitoring of health becomes a necessity, but this is expensive and labour-intensive. Early detection of febrile diseases is essential for economical and welfare reasons and to prevent the spread of disease. The goal of this study was therefore to evaluate a mobile, non-invasive technique for measuring the body temperature of cows that precludes the need for restraint of the animals.

Materials and methods An infrared thermographic imaging camera installed on a smart phone was used to measure the surface temperature of cows. In experiment 1, a metal block heated to defined temperatures was used to obtain infrared thermographic measurements (THM). The accuracy of THM made at different distances from the block and at 2 different ambient temperatures was determined. In experiment 2, non-febrile cows underwent infrared thermographic imaging, and the body regions with the highest correlations between thermographic and rectal temperature were identified. In experiment 3, THM were made in febrile and neighbouring non-febrile cows.

Results In experiment 1, the thermographic and true temperatures of the block had the strongest relationships at 0.5 and 1.0 m (r = 0.98). The ambient temperature had a significant effect on the THM, which had larger variations and greater deviations from the block temperature at 14.8 °C than at 23.8 °C. In experiment 2, the maximum temperature at the eye (r = 0.37), THM at the muzzle (r = 0.28) and the medial canthus (r = 0.27) showed the strongest relationships with the rectal temperature. After correcting the THM with the mean difference between thermographic and rectal temperatures of the non-febrile cows, sensitivities of 88, 90 and 82 %, respectively, were calculated for THM at the muzzle, eye and medial canthus in febrile cows in experiment 3. The corresponding specificities were 6, 23 and 32 %.

Conclusion and clinical relevance Based on the low specificities of the infrared THM, the thermographic imaging camera has limited usefulness for the mass screening of dairy cows for febrile conditions. Cattle falsely identified as febrile need to be separated, caught and re-examined, which causes unnecessary stress to the animal and increases labour input.