bluuebunny/crossref_metadata_2025 huggingface dataset:
Success factors for demonstration projects of small-scale stationary fuel cells in residential buildings
Authors: Simader Guenter , Vidovic Patrick
Published: January 2022

Worldwide small-scale micro-CHPs account for the largest share in the fuel cell market by units of installation (not by installed power output). Notably, the Japanese Ene-Farm program is responsible for over 400.000 micro-CHP fuel cell installations (until the end of June 2021). This is the largest worldwide deployment program and it reflects the long- and outstanding commitment of both the Japanese government and the Japanese industry to form a ‘Hydrogen Society’. In Europe, the situation is entirely different. European projects like PACE financed by the European joint undertaking for hydrogen and fuel cells give a positive impulse for fuel cell based micro-CHP, however it has to be judged as insufficient for a market transformation measure. Presently, only Germany, notably by the KFW433 program, is providing frame conditions for a rollout of fuel cell based micro-CHP systems. This article analyses the success factors for the implementation of Ene-Farm systems in Japan. It compares the different frame conditions of Japan and European countries like Austria and discusses the question whether an Ene-Farm project based on the Japanese success factors could be replicated in Austria. On a bird’s eye, a European perspective will be derived from the analysis.
An efficient composite membrane to improve the performance of PEM reversible fuel cells
Authors: Gagliardi Gabriele G. , Cosentini Carlotta , Borello Domenico
Published: January 2022

The aim of this study is to develop composite Nafion/GO membranes, varying GO loading, to be used in a Unitized reversible fuel cell comparing its performance with the baseline Nafion. Water uptake, ion exchange capacity (IEC), tensile strength, and SEM (scanning electron microscope) analysis are discussed. The SEM analysis revealed how the GO is homogeneously disposed into the Nafion matrix. The addition of GO improves the membrane tensile strength while reducing the elongation ratio. Water uptake, IEC enhance with the increasing of GO content. Regarding fuel cell mode, the performance is analysed using a polarization curve on a MEA with an effective area of 9 cm2. The composite membrane demonstrated higher mechanical strength, enhanced water uptake so higher performance in fuel cell mode. Despite the power absorbed from the electrolysis is higher when using a composite membrane, the beneficial effect in FC mode resulted in a slightly higher round trip efficiency. The GO-Nafion membrane was not able to maintain its performance with increasing the operating time, so potentially leading to a lower lifetime than the Nafion bare.
Ammonia-based Solid Oxide Fuel Cell for zero emission maritime power: a case study
Authors: Di Micco Simona , Minutillo Mariagiovanna , Mastropasqua Luca , Cigolotti Viviana , Brouwer Jack
Published: January 2022

Implementing environmentally friendly fuels and high efficiency propulsion technologies to replace the Internal Combustion Engine (ICE) fueled by fossil fuels such as Heavy Fuel Oil (HFO) and Marine Gas Oil (MGO) on board ships represents an attractive solution for maritime power. In this context, fuel cells can play a crucial role, thanks to their high energy efficiency and ultra-low to zero criteria pollutant emissions and environmental impact.

This paper performs the technical feasibility analysis for replacing the conventional diesel engine powertrain on board a commercial vessel with an innovative system consisting of ammonia-fuel-based Solid Oxide Fuel Cell (SOFC) technology.

Taking into account the size of the diesel engines installed on board and the typical cruise performed by the commercial vessel, the ammonia consumption, as well as the optimal size of the innovative propulsion system have been assessed. In particular, the SOFC powertrain is sized at the same maximum power output as the main reference diesel engine. The mass and energy balances of the ammonia-based SOFC system have been performed in Aspen PlusTM environment. The gravimetric (kWh kg−1) and volumetric (kWh m−3) energy density features of the ammonia storage technology as well as the weight and volume of the proposed propulsion system are evaluated for verifying the compliance with the ship’s weight and space requirements. Results highlight that the proposed propulsion system involves an increase in weight both in the engine room and in the fuel room compared to the diesel engine and fuel. In particular, a cargo reduction of about 2.88% is necessary to fit the ammonia-based SOFC system compared to the space available in the reference diesel-fueled ship.
Analysis of MEA’s durability under Accelerated Stress Tests that mimic realistic automotive operations
Authors: Colombo Elena , Baricci Andrea , Casalegno Andrea
Published: January 2022

This work aims at studying MEA’s ageing under single operational “mode” accelerated stress tests (AST), that were specifically designed to replicate under hydrogen/air feeding the main stressors of realistic operations in the automotive sector. A methodology for developing AST is here presented and preliminary results about the activity included. In particular, low power and high power functioning have been mimicked in a Zero-Gradient hardware, which allows a reliable materials comparison. Quantities, measurable in-situ and operando, have been tracked during ageing, like cell power, polarization curves, Pt active area, oxygen mass transport resistance, Electrochemical Impedance Spectra. The final objective is to clarify the underlying ageing mechanisms and assess the contribution of each specific operation to the MEA lifetime, focusing in particular on the cathode catalyst layer durability. Moreover, the rate of voltage loss for the new ASTs has been successfully correlated to the degradation observed under a complete driving cycle protocol.
Modelling Miniature Microbial Fuel Cells with Three-dimensional Anodes
Authors: Casula Elisa , Mascia Michele , De Gioannis Giorgia , Di Lorenzo Mirella , Isipato Marco , Muntoni Aldo , Spiga Daniela
Published: January 2022

Microbial fuel cells (MFCs) exploit the metabolic activity of electroactive microorganisms for oxidation of organic compounds and extracellular electron transfer to an external electrode. the technology is associate with very slowreaction rates, resulting in low current densities. Anodes with high specific surface should be used to increase the overall electricity generation. Carbon-based 3D materials, with high surface per unit of volume, are largely used anode materials in MFCs, although may show significant lack in efficiency due to mass transfer limitations, concentration gradients, velocity distribution and resistivity of the material. Consequently, the concomitant effect of several parameters should be assessed and quantified to design highly performing MFCs implementing 3D anode materials. In this work, miniature MFCs with 3D anodes are mathematically modelled to quantify the effect of operative parameters on performance. The model combines equations of charge conservation, mass transport phenomena, hydrodynamics, and kinetics of the involved processes under transient conditions, and provides 3D profiles with time of velocity, biofilm thickness, substrate concentration, current density and potential. The solution predicts a laminar flow, as it was expected with the low flow rates used. The concentration profiles show the consumption of substrate in the anode, with low values of local concentrations depending on organic load in the feed stream. The model also provides a versatile tool to optimise the operative conditions of the system, managing the flow arrangements to maximise either substrate removal or electricity generation.
Versatile Bioelectrochemical system for heavy metals removal
Authors: Aliaguilla Martí , Molognoni Daniele , Bosch-Jimenez Pau , Borràs Eduard
Published: January 2022

Industrial activity has resulted in heavy metals anthropogenic contamination of groundwater, especially in industrial or mining areas. Bioelectrochemical systems (BES) can be used for metals removal and recovery from aqueous solutions. In the framework of GREENER project, double-chamber BES have been adopted to treat groundwater from industrial sites containing copper, nickel and zinc (Cu, Ni and Zn), among other contaminants. Two operation modes, (i) short-circuited microbial fuel cell (MFC), and (ii) power supply driven microbial electrolysis cell (MEC, poisoning the cathode at -0.4 V vs. Ag/AgCl), were studied for metals removal at lab-scale. Two control reactors were run to evaluate metals adsorption on cathodes and membranes, and the effect of anolyte composition. Synthetic water containing different concentrations of Cu, Ni and Zn were treated, and metals removal pathways were studied. MEC and MFC performed similarly and the highest removal efficiencies were 97.1±3.6%, 50.7±6% and 74,5% for Cu, Ni and Zn respectively, from initial concentrations in the range of 1.1-1.5 mM.
Towards cost-effective soil microbial fuel cell designs
Authors: Dziegielowski Jakub , Di Lorenzo Mirella
Published: January 2022

Soil microbial fuel cell (SMFC) is a carbon-neutral energy harvesting technology that exploits the use of electroactive bacteria naturally present in soil to directly generate electricity from organic compounds. Given the simplicity of the system design, SMFCs have great potential to be used for decentralised solutions, especially in areas where access to conventional energy sources is limited. Yet, the high cost to power ratio severely limits the translation of this technology into the market. With the aim of reducing the capital cost, in this study we explore the effect of decreasing the amounts of current collector (CC) on the performance. The results demonstrate that increasing the amount of current collector per surface area of the electrode is not a feasible way of enhancing power densities, as to increase the performance by 20% and 35%, the amount of current collector would have to be increased by 150% and 300%, respectively. This highlights the importance of economic evaluations when optimising the design of a SMFC.
Testing novel multicomposite materials for electromethanogenesis
Authors: Ghiara Giorgia , Trasatti Stefano , Goglio Andrea , Cristiani Pierangela
Published: January 2022

Electromethanogenesis is an innovative technology that uses a microbial electrochemical system to produce methane from CO2, in a power-to-gas (BEP2G) concept. The results of experimental tests of new and cost-effective carbonaceous materials for electrode are presented here. The study aims at optimizing electromethanogenesis processes at laboratory level in mesothermic condition. As part of the experiments, hydrogenotrophic microorganisms (Family Metanobacteriaceae of Archaea domains) were selected from a mixed consortium taken from a biogas digestate and inoculated in double-chamber bioelectrochemical systems. The maximum amount of methane produced was 0.3 - 0.8 mol/m2g (normalized to the cathode area) with carbon cloth electrodes. Aiming at improving the methane productivity, innovative materials for the electrodes were now studied, creating porous high-surface composites, and studying nitrogen carbons doped with Cu and hydroxyapatite (Multicomposite Cu@/HAP/C), as chemical catalysts for CO2 reduction (CO2RR). The description of the procedure for the Multicomposite Cu@/HAP/C production is reported in detail.
Effect of brazing temperatures on microstructure and properties of TC4/Ti57Zr13Cu21Ni9/316L
Authors: Yang Mei , Li Shuang , Zhang Xianju , Yang Honglang , Nie Liping , Wu Xin
Published: January 2022

Titanium alloy is an important metal material with excellent specific strength, which is widely used in aerospace field, nuclear industry, chemical medicine, and military industry. In order to investigate the connection conditions of TC4 titanium alloy and 316L stainless steel at different temperatures, the braze welding measurement with Ti57Zr13Cu21Ni9 filler metal was conducted in vacuum. The microstructure, morphology and phase of the joint were characterized by SEM (scanning electron microscope), EDS (Energy Dispersive Spectrometer) and XRD (X-ray diffraction), respectively. Microhardness and shear strength of the joint at room temperature and the bonding mechanism of TC4 and 316L were also investigated. The obtained results revealed that the main phases in the diffusion layer were Ti-based solid solution and Ti-Fe (TiFe and TiFe2) intermetallic compoundsands (IMCs) the center of the braze was mainly composed of Ti-Fe IMCs, (Ti, Zr)2(Ni, Cu), Ti-based solid solution. Additionally, the increase of brazing temperature firstly increased and then decreased the average shear strength with the maximum value of 133.9 MPa at 960 °C.
Trial of Labor and Vaginal Birth after Three Previous Cesarean
Sections: Report of Two Special Cases
Authors: Fruscalzo Arrigo , Elgendi Marwa , Gantert Marcus
Published: January 2022

Background Natural childbirth could represent a deeply rooted need for
many women, even in exceptional situations such as after 3 previous caesarean
sections.

Case presentation The first patient, a 28-year-old 6th gravida
and 3rd para, first presented in the 40+3 week of pregnancy
desiring a vaginal birth, after all the other hospitals in the area had refused
her request. A detailed explanation of potential risks was given and, when 2
days later contractions started, she gave birth to a newborn of 4450 g
spontaneously, without complications. A month later, a second woman, 42 years
old, 5th gravida, 3rd para, read about the above-mentioned
case on social media and decided to attempt a natural delivery after 3 caesarean
sections at our hospital as well. She presented herself for the first time in
the 41+1 week of pregnancy in our delivery room with an onset of labor
after rupture of the membranes and gave birth on the same day, spontaneously
without complications, to a 4150 g heavy healthy newborn.

Conclusions The wish to attempt a spontaneous birth after 3 previous
caesarean sections can be deeply anchored and should be professionally
approached by obstetricians, even if counseling and management can be
challenging.
Case Series of Applications of Resting State Functional MRI in Brain Tumor Surgery: A Novel Technique
Authors: Sahu Arpita , Kurki Vineeth , Vijan Antariksh , Janu Amit , Shetty Prakash , Moiyadi Aliasgar
Published: January 2022

Background The extent of resection for brain tumors is a critical factor in determining the oncologic outcome for a patient. However, a balance between preservation of neurological function and maximal resection is essential for true benefit.

Functional magnetic resonance imaging (fMRI) is one of the approaches that augments the neurosurgeon's ability to attain maximal safe resection by providing preoperative mapping. It may not be possible to perform awake craniotomy with intraoperative localization by direct cortical stimulation in all patients, such as children and those with neurocognitive impairment. Task-based fMRI may have limited value in these cases due to low patient cooperability.

Methods In this article we present in a case-based format, the various clinical scenarios where resting state fMRI (rs-fMRI) can be helpful in guiding neurosurgical resection. rs-fMRI of the patients has been acquired on Philips 1.5 T system. Seed voxel method has been used for processing and analysis.

Conclusion rs-fMRI does not require active patient cooperation to generate useful information and thus can be a promising tool in patients unable to cooperate for task-based studies.
An Update on Secondary Bacterial and Fungal Infections and Their Antimicrobial Resistance Pattern (AMR) in COVID-19 Confirmed Patients
Authors: Boorgula Sushma Yadav , Yelamanchili Sadhana , Kottapalli Pragathi , Naga Mohini D.
Published: January 2022

Introduction Since coronavirus disease 2019 (COVID-19) has limited treatment options, concern has been raised over secondary infections and antimicrobial resistance (AMR) patterns. It has been observed that patients who were infected with COVID-19 were predisposed to develop secondary infections. The purpose of the study is to ascertain the prevalence of the bacterial and fungal coinfections in COVID-19 patients, and also to assess the AMR patterns in the obtained isolates.

Methods We have studied 200 clinical samples obtained from 122 COVID-19 positive patients. Pathogens were identified using Vitek 2 system. The demographic and clinical patterns were also observed.

Results A total of 122 patients developed secondary infections. Patients aged more than 40 years were majorly affected (p-value < 0.0001). Respiratory samples (n = 96) were predominant. Klebsiella pneumoniae (n = 68) was the most common pathogen isolated followed by Acinetobacter baumannii (n = 54) and an overall 6% rise in the Carbapenem resistance was observed in the isolates.

Conclusion To contain the secondary infections in COVID-19 patients, it is imperative to adhere to antimicrobial stewardship program and timely revise the empirical antibiotic policy.
Exceptionally durable and hard metal alloys discovered with combination technique
Authors: Johnson-Groh Mara
Published: January 2022

By exploiting the synergy between machine learning and high throughput experimentation, scientists discovered exceptional metallic glass alloys.
The onset of dissipative chaos driven by nonequilibrium conditions
Authors: Zhang Feng , Wang Jin
Published: January 2022

Dissipative chaos appears widely in various nonequilibrium systems; however, it is not clear how dissipative chaos originates from nonequilibrium. We discuss a framework based on the potential–flux approach to study chaos from the perspective of nonequilibrium dynamics. In this framework, chaotic systems possess a wide basin on the potential landscape, in which the rotational flux dominates the system dynamics, and chaos occurs with the appearance of this basin. In contrast, the probability flux is particularly associated with the detailed balance-breaking in nonequilibrium systems. This implies that the appearance of dissipative chaos is driven by nonequilibrium conditions.
Atomically thin gallium telluride nanosheets: A new 2D material for efficient broadband nonlinear optical devices
Authors: Singha Tara , Karmakar Manobina , Kumbhakar Partha , Tiwary Chandra S. , Datta Prasanta K.
Published: January 2022

Here, we experimentally demonstrate the nonlinear optical properties of atomically thin two-dimensional layered gallium telluride (GaTe). We performed open aperture and close aperture Z-scan measurements in the femtosecond regime for the spectral range of 520–700 nm to study the broadband nonlinear absorption and nonlinear refraction. Interestingly, exfoliated GaTe displays strong saturable absorption and high negative Kerr nonlinearity in this spectral range. We observed a high nonlinear refraction coefficient, n2I, of −(7.61±0.07)×10−1 cm2/GW with near band edge excitation at 700 nm. Additionally, it shows a significant nonlinear absorption coefficient, β, of −(18.02±0.20)×104 cm/GW at an intensity of 40 GW/cm2 with high modulation depth and low saturation intensity. Transient absorption spectroscopy measurement is also performed to investigate the carrier dynamics of exfoliated GaTe and to identify the physical mechanisms responsible for the optical nonlinearity, such as Pauli blocking. The measured nonlinear optical data of the exfoliated GaTe presented in this Letter will pave the way for potential application in ultrafast photonic devices like optical switching, passive Q-switching, and mode-locking, due to high Kerr nonlinearity and saturable absorption in the femtosecond regime.
A multisite decomposition of the tensor network path integrals
Authors: Bose Amartya , Walters Peter L.
Published: January 2022

Tensor network decompositions of path integrals for simulating open quantum systems have recently been proven to be useful. However, these methods scale exponentially with the system size. This makes it challenging to simulate the non-equilibrium dynamics of extended quantum systems coupled with local dissipative environments. In this work, we extend the tensor network path integral (TNPI) framework to efficiently simulate such extended systems. The Feynman–Vernon influence functional is a popular approach used to account for the effect of environments on the dynamics of the system. In order to facilitate the incorporation of the influence functional into a multisite framework (MS-TNPI), we combine a matrix product state (MPS) decomposition of the reduced density tensor of the system along the sites with a corresponding tensor network representation of the time axis to construct an efficient 2D tensor network. The 2D MS-TNPI network, when contracted, yields the time-dependent reduced density tensor of the extended system as an MPS. The algorithm presented is independent of the system Hamiltonian. We outline an iteration scheme to take the simulation beyond the non-Markovian memory introduced by solvents. Applications to spin chains coupled to local harmonic baths are presented; we consider the Ising, XXZ, and Heisenberg models, demonstrating that the presence of local environments can often dissipate the entanglement between the sites. We discuss three factors causing the system to transition from a coherent oscillatory dynamics to a fully incoherent dynamics. The MS-TNPI method is useful for studying a variety of extended quantum systems coupled with solvents.
Dispersion of heavy particles under sea waves
Authors: De Leo A. , Stocchino A.
Published: January 2022

We report the results of a series of numerical simulations performed with the aim to describe the dispersion of heavy particles transported by sea waves. Recent studies investigated the interplay between the wave Stokes drift and the inertial character of negatively buoyant particles that, ultimately, yields an augmented settling velocity. Our interest is to investigate the possible occurrence of a Brownian regime that would allow for the definition of a diffusion coefficient. The velocity and acceleration auto-correlation functions and the corresponding integral time scales show that already at a very low Stokes number the particles behave very differently from the fluid. The main consequence is that an asymptotic diffusive regime is rarely observed, except as a transient regime or when the background random noise is comparable with the wave field velocities.
A new technique for tokamak edge density measurement based on microwave interferometer
Authors: Usoltceva Mariia , Heuraux Stéphane , Khabibullin Ildar , Faugel Helmut
Published: January 2022

A novel approach for density measurements at the edge of a hot plasma device is presented—Microwave Interferometer in the Limiter Shadow (MILS). The diagnostic technique is based on measuring the change in phase and power of a microwave beam passing tangentially through the edge plasma, perpendicular to the background magnetic field. The wave propagation involves varying combinations of refraction, phase change, and further interference of the beam fractions. A 3D model is constructed as a synthetic diagnostic for MILS and allows exploring this broad range of wave propagation regimes. The diagnostic parameters, such as its dimensions, frequency, and configuration of the emitter and receiver antennas, should be balanced to meet the target range and location of measurements. It can be therefore adjusted for various conditions, and here, the diagnostic concept is evaluated on a chosen example, which was taken as suitable to cover densities of ∼1015 to 1019 m−3 on the edge of the ASDEX Upgrade tokamak. Based on a density profile with a fixed radial shape, appropriate for experimental density approximation, a database of synthetic diagnostic measurements is built. The developed genetic algorithm genMILS of density profile reconstruction using the constructed database has quite low errors. It is estimated as ∼5% to 15% for density ≥1017 m−3. Therefore, the new diagnostic technique (with a dedicated data processing algorithm) has a large potential in practical applications in a wide range of densities, with low errors in the numerical model and in the method of density reconstruction, so the total error and the density estimation accuracy are expected to be defined mostly by experimental uncertainties.
Transverse effect on liquid viscosity: A many-body dissipative particle dynamics simulation study
Authors: Ren Liuzhen , Hu Haibao , Bao Luyao , Xie Luo , Wen Jun
Published: January 2022

Fluid viscosity plays an important role in multiphase flows, and the many-body dissipative particle dynamics (MDPD) method is an efficient means of simulating such flows at the mesoscopic scale. As the viscosity of the standard MDPD (S-MDPD) fluid cannot be efficiently adjusted, a transverse MDPD (T-MDPD) scheme is newly proposed to tune the viscosity of an MDPD fluid over a large range. With a lateral friction coefficient added to the S-MDPD form, the viscosity of the T-MDPD fluid is higher than that of an S-MDPD fluid, and the viscosity is about five times larger than that of an S-MDPD fluid with a friction coefficient of 40.5. In a T-MDPD fluid, the viscosity is much more sensitive to the new transverse friction coefficient, as it increases about five times higher when this coefficient increases from 4.5 to 40.5, while the viscosity only increases two times higher with the same variation of the original coefficient. By increasing the repulsive coefficient, the liquid particle number density, or the cutoff radius, the viscosity of the T-MDPD fluid is enhanced as well. Based on this extension of the MDPD scheme, a quantitative expression for the variation of the viscosity in the current T-MDPD fluid is derived. In future simulations of multiphase flows using an MDPD scheme, the transverse effect can be extended to effectively tune the viscosity, and this empirical expression will be useful to predict the viscosity of the T-MDPD fluid.
Raman spectroscopy of the Jahn–Teller phonons in a magnetic LaMnO3 thin film grown on KTaO3
Authors: Safarina Giovanni Annur , Kim Yong-Jin , Park Heung-Sik , Yang Chan-Ho
Published: January 2022

Bulk LaMnO3 is an A-type antiferromagnetic material in which the Jahn–Teller (JT) planes each have a ferromagnetic arrangement, but are stacked in antiparallel. Here, we report the growth of epitaxial LaMnO3 films on (001)-oriented cubic KTaO3 substrates in such a way that the JT plane is parallel to the nonmagnetic substrate. We verify the presence of the JT distortion and confirm the orientation of the plane by symmetry analysis with angle-resolved polarized Raman spectroscopy. The temperature evolution of the Raman spectra indicates that the B1g JT phonon softens below the magnetic transition temperature of ∼145 K, where ferro- or ferri-magnetism with magnetic easy axis along the out-of-plane direction is exhibited.
Intermittent swimming of two self-propelled flapping plates in tandem configuration
Authors: Kang Linlin , Lu Xi-Yun , Cui Weicheng
Published: January 2022

Intermittent swimming and schooling individually offer the possibility of energy economy for fish. To study the role of the simultaneous use of both behaviors, the intermittent swimming of two self-propelled plates in tandem configuration is investigated numerically. Two intermittent swimming modes, i.e., the multiple-tail beat (MT) mode and the half-tail beat (HT) mode, are considered. For solitary plate swimming intermittently while maintaining fixed bout period, the propulsion velocity and energy consumption decrease monotonically as the duty cycle increases, consistent with the prediction of the reduced-order model. A pair of plates swimming with independent duty cycle can form orderly configurations, without separating or colliding, when their duty cycles are similar. For the MT mode, the asymmetric wake of the leader enhances the drag on the following plate by inducing an additional oncoming flow against it, making the follower harder to follow. For the HT mode, the symmetric wake of the leader reduces the drag on the follower, making it easier to follow. No significant difference was found in the propulsive performance of intermittent swimming between the leading plate in orderly configurations and solitary plate. The results of efficiency indicate that the HT mode is more economical than the MT mode for the follower. Usually, the smaller the equilibrium gap spacing is, the more efficient the follower is. The results of the cost of transport show that the follower achieves better energy economy for higher propulsion velocity. The results provide some insight into the collective intermittent swimming of fish and are helpful for bionic design.
In vitro study of cataract extraction by bursts of microsecond 1.54-μm laser pulses
Authors: Belikov A.V. , Smirnov S.N. , Batov Yu.N. , Gubin A.B. , Pirozhkov Yu.B. , Boiko E.V. , Nemsitsveridze M.N.
Published: January 2022

Laser extraction of a model porcine eye cataract has been performed for the first time in anin vitroexperiment using a 1.54-μm Yb, Er : glass laser generating bursts of microsecond pulses. We used effective pulse repetition rates from 36 to 75 Hz and average laser output powers from 3.9 to 5.25 W. The results demonstrate for the first time that, at an effective pulse repetition rate of 45 Hz, burst repetition rate of 15 Hz, three microsecond pulses per burst, and a burst energy from 260 to 265 mJ, the laser step duration in cataract extraction is 130 ± 10 s, which is comparable to the ultrasonic phacoemulsification and laser extraction time in the case of a Nd : YAG laser emitting at 1.44 μm. Acoustometry and high speed video recording of hydroacoustic processes accompanying interaction of water with 1.54-μm radiation from the Yb, Er : glass laser generating bursts of microsecond pulses have made it possible for the first time to detect overlap of hydroacoustic processes at the pulse spacing in bursts reduced to under 700 μs. In the case of overlap of hydroacoustic processes, despite the increase in average power and effective pulse repetition rate, acoustic wave generation is ineffective because pulses propagate through bubbles formed in the water. Laser cataract extraction is shown to be most effective at a lower average power, lower effective pulse repetition rate, and burst pulse spacing of 850 ± 10 μs.
Novel approaches in 3D live cell microscopy
Authors: Richter V. , Rank M. , Heinrich A. , Schneckenburger H.
Published: January 2022

Microscopy methods for 3D live cell imaging, including various techniques, challenges and restrictions, are described. Novel devices for application of these methods in combination with 3D printed optics are presented and discussed.
Estimation of a minimum laser power with wavelengths of 1.47, 1.56, and 1.68 μm for efficient obliteration of varicose veins
Authors: Ignat’eva N.Yu. , Zakharkina O.L. , Sviridov A.P. , Mazaishvili K.V. , Shekhter A.B.
Published: January 2022

Experiments modelling endovenous laser obliteration (EVLO) are performed. As a result, laser radiation powers P
c at which collagen denaturation, tissue necrosis, and vasa vasorum destruction occur throughout the entire venous-wall thickness and, at the same time, the surrounding tissues are not subjected to unnecessary heating, are found. The main criterion for determining P
c is the achievement of 100 % denaturation of venous-wall proteins, confirmed by morphological and calorimetric analysis. The P
c values for laser wavelengths of 1.47, 1.56, and 1.68 μm are found to be 6.0 ± 0.2, 5.0 ± 0.2, and 6.0 ± 0.2 W, respectively. It is established for all wavelengths in use that the temperature of the external venous-wall surface reaches 91 ± 2 °C at the corresponding power P
c. We relate the dependence of P
c on the radiation wavelength to the formation of a coagulum on the optical fibre tip moving through a blood-filled vessel. The achievement of temperature necessary for coagulum formation is determined by the simultaneously occurring processes of energy absorption and its dissipation in the form of heat. These processes become more intense with an increase in the absorption coefficient of the medium. A mechanism is proposed to explain the relationship between the P
c value and laser wavelength, based on the influence of the absorption coefficient of medium (blood) on the temperature near the fibre tip.
Inactivation of coronaviruses under irradiation by UVA-range light-emitting diodes
Authors: Zavestovskaya I.N. , Gushchin V.A. , Russu L.I. , Cheshev E.A. , Koromyslov A.L. , Tupitsyn I.M. , Fronya A.A. , Grigoryeva M.S.
Published: January 2022

We report the results of the development of an experimental stand based on UVA light-emitting diodes (UVA LEDs) with radiation wavelengths of 385 and 395 nm for studying experimentally the inactivation of viruses of the coronavirus family, including SARS-CoV-2. Methodological grounds are presented for determining the inactivation dose that provides a predetermined decrease in the virus titre under the impact of UVA radiation. The effect of the diode radiation divergence on the virus photoinactivation process is investigated. It is shown that UVA LEDs can be used to reduce the virus titre by 4 orders of magnitude.
Global evidence on the selfish rich inequality hypothesis
Authors: Almås Ingvild , Cappelen Alexander W. , Sørensen Erik Ø. , Tungodden Bertil
Published: January 2022

Significance

People’s beliefs about why the rich are richer than the poor have the potential to affect both policy attitudes and economic development. We provide global evidence showing that where the fortunes of the rich are perceived to be the result of selfish behavior, inequality is viewed as unfair, and there is stronger support for income redistribution. However, we also observe that belief in selfish rich inequality is highly polarized in many countries and thus a source of political disagreement that might be detrimental to economic development. We find systematic country differences in the extent to which people believe that selfishness is a source of inequality, which sheds light on international differences in public morality, civic virtues, and redistributive policies.
Direct visualization of polaron formation in the thermoelectric SnSe
Authors: René de Cotret Laurent P. , Otto Martin R. , Pöhls Jan-Hendrik , Luo Zhongzhen , Kanatzidis Mercouri G. , Siwick Bradley J.
Published: January 2022

Significance

Thermoelectrics can generate electrical power from waste heat and could make an important contribution to sustainable energy production if their efficiency is improved. Engineering efficient thermoelectrics, however, requires a sophisticated understanding of the fundamental interdependencies between electrical and thermal transport, for which improvements in our understanding of how charge carriers are coupled to lattice vibrations (phonons) is needed. Using advanced ultrafast electron-based techniques, we probe the fundamental nature of electron–phonon coupling in SnSe, one of the highest-performing thermoelectric materials, in order to unravel the origins of its thermoelectric efficiency. We show that the charge carriers in SnSe interact strongly with lattice waves to form moving lattice distortions called polarons, which helps to explain some of SnSe’s most unusual properties.
Unraveling the origin of extra strengthening in gradient nanotwinned metals
Authors: Cheng Zhao , Bu Linfeng , Zhang Yin , Wu HengAn , Zhu Ting , Gao Huajian , Lu Lei
Published: January 2022

Significance

The emergence of heterogeneous nanostructured metals offers exciting opportunities for achieving extraordinary mechanical properties. Gradient nanotwinned Cu is a prominent class of heterogeneous nanostructured metals, as it exhibits a superior extra strength compared with nongradient counterparts. However, the mechanistic origin of the extra strength remains elusive. At a more fundamental level, the strengthening effects of plastically inhomogeneous deformation in heterogeneous nanostructured metals are not well understood. Here, we use a combination of controlled material processing, back-stress measurement, dislocation microstructure characterization, and strain gradient plasticity modeling to unravel the origin of the extra strength in gradient nanotwinned Cu. The combined experimental and modeling framework may be applied to accelerate the rational design of heterogeneous nanostructured metals with enhanced mechanical performance.
The carbohydrate economy of fruit trees.
Authors: DeJong T. M.
Published: January 2022

Since lack of water is a commonly occurring condition in nature, plants have developed many physiological responses to help them survive periods of water stress. Most of these responses cause changes in the carbohydrate economy of the tree through reduced photosynthesis, tree growth or cropping, but some of these effects can be managed to have minimal impact on overall tree productivity. Whether these responses influence economic production depends on: (i) the processes occurring at the time of a stress; (ii) how important these processes are to tree yield; and (iii) whether these processes rely heavily on the current level of photosynthesis or can use stored carbohydrates, like starch, to compensate for the lack of current photosynthesis in the leaves. This chapter discusses the carbohydrate economy of fruit trees. An outline is provided for how assimilates are distributed and used within a fruit or nut tree.
Understanding the shoot sink.
Authors: DeJong T. M.
Published: January 2022

To more fully understand how all the major organs of a tree interact in the semi-autonomous scheme of assimilate distribution and tree functioning, it is important to understand their development and growth behavior. This chapter presents a general description of the development and growth characteristics of the major organs (shoot and leaf) of fruit trees, including shoot structure, morphology and orientation; diurnal patterns of shoot growth; seasonal growth patterns of shoot growth and dormancy; as well as tree aging.
How to induce protective humoral immunity against Plasmodium falciparum circumsporozoite protein
Authors: Wahl Ilka , Wardemann Hedda
Published: January 2022

The induction of protective humoral immune responses against sporozoite surface proteins of the human parasite Plasmodium falciparum (Pf) is a prime goal in the development of a preerythrocytic malaria vaccine. The most promising antibody target is circumsporozoite protein (CSP). Although PfCSP induces strong humoral immune responses upon vaccination, vaccine efficacy is overall limited and not durable. Here, we review recent efforts to gain a better molecular and cellular understanding of anti-PfCSP B cell responses in humans and discuss ways to overcome limitations in the induction of stable titers of high-affinity antibodies that might help to increase vaccine efficacy and promote long-lived protection.
The physics remote laboratory: implementation of an experiment on standing waves
Authors: Caetano Thiago , Rezende Junior Mikael Frank , Pina da Silva Agenor , Moreira Camila Cardoso
Published: January 2022

There always have been some hurdles when it comes to the adequate use of didactical experimental activities in science education, such as the lack of proper training, insufficient time, and inadequate infrastructure. At this very moment, the pandemic has taught us that there may be also circumstances in which the traditional laboratory and the traditional activities are just not possible, thus online operable experiments might constitute a viable alternative for the practical lessons in higher education. In this paper, we discuss the development and the implementation of a remote-controlled didactical experiment on standing waves largely used in the physics basic program offered to the engineering courses. The development has combined applied knowledge from different areas, i.e. electric and electronics engineering, and computer science. In order to ascertain the experiment consistency, we have gathered data from the wave propagation speed and from the corresponding tension applied to the string and performed a χ-square linear fit in order to determine the correlation between the logarithm of both parameters. The experiment was successfully implemented and has been accessed by hundreds of different users from more than 30 different countries ever since. It has also been largely employed in practical activities at the university and has shown no significant signs of instability. It exhibited a total latency time inferior to 0.8 s on average and the results drawn from data it provides have shown to be accurate, within less than 0.8% of deviation with respect to the theoretical results.
Highly sensitive flexible modulus sensor for softness perception and clinical application
Authors: Zou Qiang , Yang Fengrui , Wang Yaodong
Published: January 2022

The wearable sensors for softness measuring are emerging as a solution of softness perception, which is an intrinsic function of human skin, for electronic skin and human-machine interaction. However, these wearable sensors suffer from a key challenge: the modulus of an object can not be characterized directly, which originates from the complicated transduction mechanism. To address this key challenge, we developed a flexible and wearable modulus sensor that can simultaneously measure the pressure and modulus without mutual interference. The modulus sensing was realized by merging the electrostatic capacitance response from the pressure sensor and the ionic capacitance response from the indentation sensor. Via the optimized structure, our sensor exhibits high modulus sensitivity of 1.9 × 102 in 0.06 MPa, a fast dynamic response time of 100 ms, and high mechanical robustness for over 2500 cycles. We also integrated the sensor onto a prosthetic hand and surgical probe to demonstrate its capability for pressure and modulus sensing. This work provides a new strategy for modulus measurement, which has great potential in softness sensing and medical application.
Controlling magnetic-semiconductor properties of the Si- and Al-doped blue phosphorene monolayer
Authors: On Vo Van , Guerrero-Sanchez J , Hoat D M
Published: January 2022

Doping has been widely employed as an efficient method to diversify a materials properties. In this work, the structural, magnetic, and electronic properties of pristine aluminum (Al)-, and silicon (Si)-doped blue phosphorene monolayer are investigated using first-principles calculations. Pristine monolayer is a non-magnetic, wide gap, semiconductor with a band gap of 1.81 eV. The 1Si-doped system is a ferromagnetic semiconductor. However, the magnetism is turned off when increasing the dopant composition with small Si–Si distance. Further separating the dopants recovers, step by step, the magnetic properties and an antiferromagnetic (AFM)-ferromagnetic (FM) state transition will take place at large dopants separation. In contrast, Al doping retains the non-magnetic semiconductor behavior of blue phosphorene. However, significant energy gap reduction is achieved, where this parameter exhibits a strong dependence on the dopant concentration and doping configuration. Such control may also induce the indirect-direct gap transition. Our results introduce prospective two-dimensional (2D) materials for application in spintronic and optoelectronic nano devices, which can be realized and stabilized in experiments as suggested by the calculated formation and cohesive energies.
Ultra-sensitive all-optical comagnetometer with laser heating
Authors: Zhao Tian , Liu Ying , Wei Kai , Xie Hongtai , Mu Tangjie , Fang Xiujie , Xu Zitong , Zhai Yueyang
Published: January 2022

Ultra-sensitive comagnetometers, which are designed to detect nuclear- and electron-spin-dependent interaction, have important applications ranging from basic research to inertial navigation systems (INSs). Unfortunately, electric heating, which is typically used in comagnetometers, introduces noise and instability because of the unavoidable generation of a modulated magnetic field. In this study, we investigate and introduce a K-Rb-21Ne comagnetometer that uses laser heating for the first time, when operated in the spin exchange relaxation free regime. The performance of the comagnetometer, which is equipped with both laser heating and electric heating, is investigated, and the two heating modes are compared. The temperature characteristics of the comagnetometer are studied theoretically and experimentally. By optimizing the operating temperature and power density of the pump-light, an equivalent rotation sensitivity of

2.5
×

10

−
7

rad−1 s−1 Hz

1
/
2

@1 Hz is achieved in laser heating mode. The improvement of laser-heating technology could prove essential to reduce electron relaxation and increase the low-frequency sensitivity of comagnetometers. Our results indicate that laser heating can make comagnetometers more suitable for applications in basic research (fifth forces, dark matter, etc), INSs, and other accurate measurements of electronic and nuclear precession.
Self-consistent simulation of the impedance matching network for single frequency capacitively coupled plasma
Authors: Gao Jiamao , Yu Shimin , Wu Hao , Wang Yu , Wang Zhijiang , Pan Yuan , Jiang Wei , Zhang Ya
Published: January 2022

Matching networks are of vital importance for capacitively coupled plasmas (CCPs) to maximize the power transferred to the plasma discharge. The nonlinear interaction between the external circuit and plasma has to be considered to design suitable matching networks. To study the effect of the matching circuit, we coupled particle in cell/MC(Monte Carlo) model and nonlinear circuit equations based on Kirchhoff’s laws, in a fully nonlinear and self-consistent way. The single-frequency capacitively coupled discharge with ‘L’-Type matching networks are simulated. Fully self-consistently results of circuit and plasma parameters are presented and then power absorbed by the plasma and efficiency are calculated. With the tune of the matching network, the efficiency can reach 28.7%, leading to higher potential as well as higher electron density at fixed source voltage. Besides, only very small components of the third harmonics are found in the plasma voltage and current while surface charge densities have multiple harmonics on account of the strong plasma nonlinearity. Finally, the effects of matching capacitors on discharge are analyzed, results show that smaller

C

m
1

and

C

m
2

of 500–1000 pF may be a proper choice for better matching, resulting in higher voltage across the CCP, and thus higher electron density and power absorption efficiency are obtained.
Analysis of bistability at the coupling between waveguide and whispering gallery modes of a nonlinear hemicylinder
Authors: Parsamyan Henrik , Sahakyan Khachik , Nerkararyan Khachatur
Published: January 2022

The optical bistability caused by the coupling between modes of the parallel-plate waveguide and a nonlinear hemicylindrical crystal is studied using theoretical and numerical analysis. In such a system a waveguide channel is parallelly coupled to whispering gallery modes (WGMs) of a hemicylindrical microresonator ensuring bistable behaviour at input intensities of the order of a few MW cm−2. The characteristic minimum switching time of the system (around 30 ps) can be controlled by varying the thickness of the metal layer which couples the waveguide and WGMs. This is conditioned by the change of the qualityQ-factor, as well as the coupling coefficient of the resonator. The main advantages of the system are fabrication simplicity, small sizes of the order of 3µm, integrability with other optical components and the possibility of adjusting the processes by making use of the electro-optical effect.