bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design Strategies to Overcome EMI/EMC Issues of Airborne Receivers
Authors: Sarkar Mahadev , Raghu B R 
Published: May 2022

Abstract
This article describes various housing design strategies of a complex receiver system to overcome EMI/EMC challenges for airborne system applications. Isolation of leakage energy between various RF/DC-DC converters/Regulators/pulsing blocks are the key target of this design to keep conductive and radiative emission minimum. Hence, complex receiver design has been segregated into various modules. Block level design is carried out using 3D EM simulator to assess the leakage. Then they are stacked together very tactfully within the specified area without compromising inter-channel/module interference between them and the form factor respectively. The super compact stacks are further channelized for RF, DC supply, controls etc. and protected them from any kind of interferences. Low cost flexi interconnects are made to interface various stacks to arrest unwanted high/low frequency leakages. Finally, receiver module is developed and tested over temperature and EMI/EMC successfully to establish the methodology.
Detection and Classification of Target’s Speed and Size Using LTE-Based Passive Forward Scattering Radar
Authors: Abdul Aziz N H , Abdul Hadi M F , Abd Rahman N H , Alias A J , AL-Hiealy M R J 
Published: May 2022

Abstract
Radar is a system that uses radio waves to detect any objects that pass through the range of its system. The radar system must have two main components which are the transmitter and the receiver. The passive forward scattering radar is being used to detect the target’s speed and size. This passive radar uses the cell tower of Long-Term Evolution (LTE) as a transmitter and will illuminate any moving targets that pass through the system. The passive radar receiver which can be remotely placed will detect the scattered radiation of the target. The detection of the target is in a waveform called the Doppler signature. From the Doppler signature, the target’s speed and size can be classified according to its group. In this research, a different target has a different Doppler signature because every target’s body has a different body build. The differences in Doppler signature also can be detected when the target moves at different speeds. The study of different speed targets will relate to the relationship between the time and frequency theory. The data collection of Doppler signature is collected in three different places which are Universiti Teknologi MARA (UiTM, Shah Alam), Kampung Sungai Kajang (Tanjung Karang), and Malaysia Agro Exposition Park Serdang (MAEPS) (Serdang). In conclusion, the LTE-based passive forward scattering radar system is applicable to detect and classify every target with different speed and size which is useful to the country’s border safety and security system.
Why total solar eclipses are important to science?
Authors: Tsvetkov Ts , Petrov N 
Published: May 2022

Abstract
Despite today we have plenty of opportunities for high-quality observations of the Sun from both Earth and space, total solar eclipses remain a rare chance to explore the corona, its features and various atmospheric phenomena. Members of our team took part of 5 out of 6 Bulgarian expeditions for total solar eclipse observations ever realized. In the current paper we summarize the tasks we fulfilled and the scientific results we obtained. Special attention is paid to the investigation of the shadow bands that accompanied the last eclipse we witnessed – on 2019 July 2.
Observational features of thin accretion disks around traversable wormholes
Authors: Deliyski V , Gyulchev G , Nedkova P , Yazadjiev S 
Published: May 2022

Abstract
We investigate the potential appearance of qualitatively new observational features of accretion disk images around compact objects. More specifcally we focus on a particular class of traversable wormholes, possessing a photon sphere. We discover that for certain solution parameters the shape of the images produced possesses distinct features that are not present for Kerr black holes. This provides potential avenues for diferentiating between compact objects based on observational data at the scale of the gravitational radius.
Observational features of hot spots on neutron stars with a photon sphere
Authors: Gyulchev Galin 
Published: May 2022

Abstract
We describe and illustrate light deflection near neutron stars possessing a photon sphere motivated by modern confirmations of general relativity and its significance for relativistic astrophysics. In this paper, we model the spacetime outside the star with the Schwarzschild metric and summarize the properties of the photon orbits. More especially we illustrate the relativistic appearance of the hot spots on the neutron star surfaces over the celestial screen of an asymptotic observer. We visualize the relativistic images of the neutron star surface for various ratios of neutron star radius to Schwarzschild radius. We establish a noticeable increscent of the visual size of ultra-compact neutron stars with a photon sphere, which could distinguish stars with extremely strong surface gravity with respect to less compact neutron stars. We found an appearance of additional relativistic images of the hot spots leading to a higher magnification of the neutron star luminosity emission regions.
Impact Point Determination of Gamma Interaction in a Monolithic Scintillator Crystal Read Out by a SiPM Matrix
Authors: Ivanov Svetoslav , Ivanov Simeon 
Published: May 2022

Abstract
We construct a simulation framework which can determine simultaneously deposited energy, position and time resolution of interactions of gamma rays in a monolithic scintillator crystal read out by a matrix of photosensitive detectors. And we report and discuss the simulation results form three different methods to determine the impact position of a particle.
Geomagnetic control of cosmic radiation and its impact on the irregularly distributed lower stratospheric ozone
Authors: Kilifarska N A , Peqini K 
Published: May 2022

Abstract
This article has two main objectives: (i) to elucidate the impact of non-dipolar part of geomagnetic field on the spatial distribution of cosmic radiation received over the globe, and (ii) to establish the influence of particles (with different origin and energies) on the atmospheric ozone profile. Our analyses show more evidence that lower stratospheric ozone at subtropics is sensitive to the radiation trapped by geomagnetic filed in Van-Allen radiation belts. At the same time, the high latitude ozone is vulnerable to the solar plasma, hitting the Earth after solar proton events.
Future trends of commercial In- Orbit Satellite Servicing, Active Debris Removal and End-Of Life services
Authors: PhD Stella Alexandrova 
Published: May 2022

Abstract
Space debris growth has become a major threat not only to satellites as well as to the safe operations of the International Space Station (ISS). In September 2021, there were more than 4,700 operational satellites, 36,5000 space debris objects larger than 10 cm and 1 000 000 pieces in the 1cm to 10 cm range. The total mass of all space objects in Earth Orbit is 9,600 tonnes[1]. The launches of Starlink, Amazon Kuiper and OneWeb satellite constellations will increase the threat of space debris collisions.
Satellite owners, operators, space agencies and commercial players owning the mega-constellations will need to find economically viable ways to inspect, refuel, augment, extend and manage the lifetime of their satellites. Some of the emerging trends taking place in the space industry are on- orbit satellite servicing, active debris removal services and end-of life services. With the technology demonstrations on orbit of Mission Extension Vehicles (MEV-1), MEV-2 and ELSA-d missions promising In Orbit Satellite (IOS), markets are emerging and expected to reach up to $ 6.2 bln by 2030[2]. The objective of this paper is to identify the role of Bulgarian organisations in the future emerging of in- orbital satellite (IOS) and space situational services markets. Bulgaria’s historical space competencies can contribute to the development of user-driven services/ solutions for space debris inspection, collision avoidance, space robotics and in- orbit servicing and assembly. By encouraging the creation of a new space eco-system in the domain of space debris and space situational awareness in South-Eastern Europe, Bulgarian companies and research organisations are bound to play an important role in the future space robotics markets.
Analysis of hyperspectral and multispectral reflectance spectra in the Black Sea coastal area near the Danube delta: comparison of PRISMA and Sentinel-2 observations
Authors: Gancheva Irina 
Published: May 2022

Abstract
In this study we investigate the possibility to distinguish between different water types in the Danube delta and the Black Sea coastal zone based on the reflectance spectra. For this we use hyperspectral satellite images from PRISMA (PRecursore IperSpettrale della Missione Applicativa) and multispectral images from Sentinel-2 MSI (MultiSpectral Instrument) in July 2020.
The visual inspection of the available acquisitions differentiates between four aquatic types: lagoons; river and stream plumes mixing with marine waters; turbid and optically complex coastal waters; and optically clean waters away from the shore. For each of the four types we determine the characteristic averaged reflectance spectra from PRISMA and Sentinel-2 for the spectral range from 400 nm to 2500 nm. It is found that Sentinel-2 spectra are very similar for the 4 water types, in contrast to the PRISMA spectra which give substantial additional information.
Further we analyse the gradual modification of the characteristic hyper- and multispectral spectra from the shoreline to the open sea (∼25 km distance) in 15 locations passing through areas of varying turbidity. We demonstrate that the intensity of surface reflectance from the hyperspectral instrument decreases gradually with distance from shoreline, clearly showing the transition zone between riverine and marine water. The multispectral reflectance spectra for the same study areas did not present such consistent behaviour.
The presented results demonstrate the benefits of hyperspectral over multispectral images for turbid aquatic regions in the Black Sea coastal zone. They show that with little requirements regarding pre-processing and computational resources hyperspectral data can contribute greatly to classification of water types, in respect of their turbidity.
Surface impacts of large offshore wind farms
Authors: Golbazi Maryam , Archer Cristina L , Alessandrini Stefano 
Published: May 2022

Abstract
Future offshore wind farms around the world will be built with wind turbines of size and capacity never seen before (with diameter and hub height exceeding 150 and 100 m, respectively, and rated power exceeding 10 MW). Their potential impacts at the surface have not yet been studied. Here we conduct high-resolution numerical simulations using a mesoscale model with a wind farm parameterization and compare scenarios with and without offshore wind farms equipped with these ‘extreme-scale’ wind turbines. Wind speed, turbulence, friction velocity, and sensible heat fluxes are slightly reduced at the surface, like with conventional wind turbines. But, while the warming found below the rotor in stable atmospheric conditions extends to the surface with conventional wind turbines, with extreme-scale ones it does not reach the surface, where instead minimal cooling is found. Overall, the surface meteorological impacts of large offshore wind farms equipped with extreme-scale turbines are statistically significant but negligible in magnitude.
Concrete consoles impact to a masonry walls building with a large hall at the top story and a lightweight timber roof
Authors: Constantinescu S 
Published: May 2022

Abstract
The paper studies the behavior of a medium height masonry walls building, placed in Satu Mare (Romania). It contains large balcony consoles and a large hall at the top story, covered by a timber roof. The roof trusses sit at both ends on the external walls. The study’s purpose is to determine the importance of large slab consoles and walls buttresses at the top story, for the structure. The paper compares the structure’s behavior in 3 cases. The first contains both large consoles and wall spurs, the second only incorporates pier buttresses and the third holds just the balcony consoles. The structure’s behavior for both the elastic and plastic stage is compared for the 3 cases. The plastic stage shows the bending moment’s distribution in slabs and stresses in masonry walls during stages when they surpass the masonry strengths. The plastic hinges development at structure collapse and the pushover diagrams for each case along with the results interpretation are presented. A nonlinear analysis is done for the timber roof also, for both orthogonal directions. The study shows both large consoles and halls at the top floor are appropriate for masonry structures, if designed correctly.
Plane shape impact to non-bearing masonry walls in a high rise reinforced concrete walls building
Authors: Constantinescu S 
Published: May 2022

Abstract
Nowadays, due to architectural necessities, structures have emerged in many different plane shapes, such as U, V, L T and others. It is important to establish if a nonrectangular shape causes important changes both for the bearing and non-bearing elements, compared to a rectangular one. The paper shows the impact a buildings shapes on the partitioning walls. For this paper the structures in study are two high rise reinforced concrete walls buildings placed in a high seismic area (Bucharest, Romania). The partitioning walls are made of masonry. Both bearing and non-bearing walls are the same for both buildings. They are just placed in different locations, so that the structures have different shapes in plan. One has the shape of an I and the other of a V. The paper studies the buildings behavior in both cases. The masonry walls stresses are analysed for both the elastic and plastic stage. The conclusion is that in this case, for these shapes, the non-bearing walls are not affected very much by the building’s plane shape.
Assessing the vulnerability of buildings to floods in the lower sector of Slănic River. Case Study of Cernăteşti village, Buzău County, Romania
Authors: Costache R , Popescu C , Barbulescu A 
Published: May 2022

Abstract
Assessing the vulnerability of buildings is very important to determine the settlements affected by floods since authorities can take measures before actual flooding takes place. The present research aims to identify areas affected by flooding in Cernăteşti. The village is located in an area where floods are favored by the elongated shape of the catchment, the horizontal slope, relatively small distance between the hills bordering the valley, water accumulation resulting from flash floods formed upstream, and heavy local rainfall. Field observations, GIS techniques, and mathematical calculations have been used in this research. Flood simulations have been made to determine the degree (number of houses and roads affected, estimated losses in lei) of impact at flows with different probabilities of exceedance (10%, 5%, 2%, and 1%). Depending on the exposure, calculated using factors like distance from the river or construction material, the buildings on the left bank of Slănic are more affected and the flooded area is more extensive. Buildings in the south-eastern, north-eastern, and north-western parts of the flooded area are highly vulnerable, but most of the other settlements are less vulnerable.
Numerical model validation of non-composite slim floor beam subjected to fire
Authors: Duma D , Zaharia R , Pintea D , Both I 
Published: May 2022

AbstractCompared to traditional composite steel-concrete beams, where the concrete slab is supported by the top flange of a steel profile, in slim floor systems, the beam is integrated into the height of the concrete slab. These configurations are popular due to their cost-effectiveness and fire performance. However, fire design requires advanced calculation models, as Eurocodes do not provide a simplified method for the analysis of these types of beams when exposed to fire. The validation of the numerical models is an important issue for researchers, designers, software developers, and authorities. The European Standard for the fire design of composite steel and concrete structures, EN 1994-1-2, states that advanced calculation models must be validated against experimental test results. The paper presents the validation of a numerical model, for the thermal and mechanical analysis of slim floor beams, using SAFIR software. SAFIR is a special purpose computer program, based on the Finite Element Method, developed for the analysis of structures under elevated temperature conditions. The model is validated against an existing experimental fire test, available in the literature. The temperatures on the cross-section and the vertical beam displacements obtained numerically are reproducing very well the experimental results.
Stiffness analysis of rolling bearing for concrete mixer
Authors: Wang Z , He W Z , Niu S Q 
Published: May 2022

Abstract
According to the rolling bearing geometry, the basic principle of kinematics and Hertz elastic contact theory, eccentric mass of mixing shaft, the centrifugal force of steel ball and gyroscopic moment are considered and the dynamic model of angular contact ball bearing is established in this paper. Using this model, the effects of preload, radial load and rotating speed on bearing stiffness and system dynamic characteristics are analyzed in detail. The results show that with the increase of radial load, the axial static stiffness decreases, while the radial stiffness increases gradually, and the increasing trend of radial static stiffness is more obvious than that of axial static stiffness. The increase of rotating speed will soften the stiffness of the bearing. The natural frequencies of each order of the system show a downward trend with the increase of rotating speed.
Completeness of 𝑝-Weil-Petersson distance
Authors: Yanagishita Masahiro 
Published: May 2022

Our goal of this paper is to research the completeness of the

p
p

-Weil-Petersson distance, which is induced by the

p
p

-Weil-Petersson metric on the

p
p

-integrable Teichmüller space of hyperbolic Riemann surfaces. As a result, we see that the metric is incomplete for all the hyperbolic Riemann surfaces with Lehner’s condition except for the ones that are conformally equivalent to either the unit disk or the punctured unit disk. The proof is based on the one by Wolpert’s original paper, which is given in the case of compact Riemann surfaces.
The Features of 24-Hour Urine and Paired Serum Electrolytes in Hypertensive Patients With Primary Aldosteronism
Authors: Wang Meng-hui , Cai Li , Luo Qin , Zhang De-lian , Hu Jun-li , Zhang Wei-wei , Zhao Jian-wen , Li Nan-fang 
Published: May 2022

Abstract

Background
To investigate the features of 24-hour urine and paired serum electrolytes in hypertensive patients with primary aldosteronism (PA).

Methods
A total of 764 hypertensive patients, who underwent PA screening and completed the measurement of 24-hour urine and paired serum electrolytes from January 2009 to January 2014 at the Hypertension Center of People’s Hospital of Xinjiang Uygur Autonomous Region, were included. Of which, 135 patients were diagnosed with PA, whereas 629 patients were non-PA patients.

Results
Compared with the non-PA group, serum potassium (3.66 ± 0.41 vs. 3.86 ± 0.37 mmol/L), serum phosphorus (1.08 ± 0.16 vs. 1.16 ± 0.19 mmol/L), and calcium–phosphorus product (29.7 ± 5.2 vs. 32.4 ± 6.9 mg2/dL2) were lower in the PA group, while urine potassium (41.5, 31.6–52.4 vs. 35.9, 27.7–46.3 mmol/L), urine calcium (6.0, 4.5–8.1 vs. 5.2, 3.9–6.9 mmol/L), urine magnesium (3.8, 3.1–5.0 vs. 3.5, 2.7–4.6 mmol/L), the ratio of blood sodium to urine sodium divided by the ratio of blood potassium squared to urine potassium (SUSPPUP) (2.48, 1.71–3.95 vs. 1.96, 1.39–2.73) were higher in PA group (P &lt; 0.01). Hypokalemia, hypocalcemia, urinary potassium &gt; 54.1 mmol/L, urinary calcium &gt; 7.5 mmol/L, and calcium–phosphorus product &lt; 35 mg2/dL2 were more frequently observed in PA patients (P &lt; 0.05).

Conclusions
In addition to hypokalemia and hypocalcemia, hypertensive patients with PA have higher urinary potassium, magnesium, calcium excretion but lower serum phosphorus. Their electrolyte characteristics show a higher SUSPPUP ratio and a lower calcium–phosphorus product.
Iridescence untwined: honey bees can separate hue variations in space and time
Authors: Ng Leslie , Ospina-Rozo Laura , Garcia Jair E , Dyer Adrian G , Stuart-Fox Devi 
Published: May 2022

Abstract
Iridescence is a phenomenon whereby the hue of a surface changes with viewing or illumination angle. Many animals display iridescence but it currently remains unclear whether relevant observers process iridescent color signals as a complex collection of colors (spatial variation), or as moving patterns of colors and shapes (temporal variation). This is important as animals may use only the spatial or temporal component of the signal, although this possibility has rarely been considered or tested. Here, we investigated whether honey bees could separate the temporal and spatial components of iridescence by training them to discriminate between iridescent disks and photographic images of the iridescent patterns presented by the disks. Both stimuli therefore contained spatial color variation, but the photographic stimuli do not change in hue with varying angle (no temporal variation). We found that individual bee observers could discriminate the variable patterns of iridescent disks from static photographs during unrewarded tests. Control experiments showed that bees reliably discriminated iridescent disks from control silver disks, showing that bees were processing chromatic cues. These results suggest that honey bees could selectively choose to attend to the temporal component of iridescent signals to make accurate decisions.
RBP-TSTL is a two-stage transfer learning framework for genome-scale prediction of RNA-binding proteins
Authors: Peng Xinxin , Wang Xiaoyu , Guo Yuming , Ge Zongyuan , Li Fuyi , Gao Xin , Song Jiangning 
Published: May 2022

AbstractRNA binding proteins (RBPs) are critical for the post-transcriptional control of RNAs and play vital roles in a myriad of biological processes, such as RNA localization and gene regulation. Therefore, computational methods that are capable of accurately identifying RBPs are highly desirable and have important implications for biomedical and biotechnological applications. Here, we propose a two-stage deep transfer learning-based framework, termed RBP-TSTL, for accurate prediction of RBPs. In the first stage, the knowledge from the self-supervised pre-trained model was extracted as feature embeddings and used to represent the protein sequences, while in the second stage, a customized deep learning model was initialized based on an annotated pre-training RBPs dataset before being fine-tuned on each corresponding target species dataset. This two-stage transfer learning framework can enable the RBP-TSTL model to be effectively trained to learn and improve the prediction performance. Extensive performance benchmarking of the RBP-TSTL models trained using the features generated by the self-supervised pre-trained model and other models trained using hand-crafting encoding features demonstrated the effectiveness of the proposed two-stage knowledge transfer strategy based on the self-supervised pre-trained models. Using the best-performing RBP-TSTL models, we further conducted genome-scale RBP predictions for Homo sapiens, Arabidopsis thaliana, Escherichia coli, and Salmonella and established a computational compendium containing all the predicted putative RBPs candidates. We anticipate that the proposed RBP-TSTL approach will be explored as a useful tool for the characterization of RNA-binding proteins and exploration of their sequence–structure–function relationships.