bluuebunny/crossref_metadata_2025_split huggingface dataset:
MIMO radar signals with better correlation characteristics
Authors: Bezoušek Pavel , Karamazov Simeon 
Published: August 2020

Abstract
MIMO radars employ multiple transmitting and receiving antennae. For each transmitting antenna, an independent and easily distinguishable signal is required, and appropriate filters must be used by the receiver. For this, the transmitted signals should have characteristics, enabling their effective separation. In this paper the correlation characteristics of selected signals are compared, and the appropriate signal coding is suggested. For differentiation, we address signals with basic linear or nonlinear frequency modulation (LFM or NLFM) multiplied by Gold, PRN, or frequency diversity (FD) codes. The analysis shows that better signal characteristics are achieved using the FD than the other codes. Using matched filters with filter length of 511, sidelobes and cross-correlations are suppressed by 40 dB with FD codes, while with the other codes only 20 dB was achieved. It was also proven, that the FD codes are more tolerant to the Doppler shift. On the other hand, the FD codes application leads to an extension of the overall transmitted signal bandwidth. This however, only represents a serious barrier for very broadband radar systems.
Risk assessment of forest decline by application of geostatistics and multi-criteria analysis
Authors: Jokanović Vesna Nikolić , Vulević Tijana , Lazarević Katarina 
Published: August 2020

Abstract
In this paper, the risk zone mapping of declining lowland forests belonging to „Morović“, management unit „Varadin-Županja“ (northern Serbia) is performed using geostatistics analysis. Based on the monitoring of groundwater level, the Kriging method has been performed for the spatial distribution of groundwater level for a multiyear period (2010–2013) – reference level and characteristic levels for the wettest and the driest year during the analyzed period. Risk assessment was determined by the variance of characteristics compared to reference levels. Then, multi-criteria decision analysis methods (AHP, PROMETHEE II) were applied to define the rank of each department (smaller forest management units) located in the research area. These analyses are very important because they enable to locate of the area with a high risk of forest decline and to rank departments using criteria: deviation from water level recorded during dry periods, species demand for water, conservation status and purpose of the unit (seed stands or technical wood). The proposed methodology is usable for the determination of the primary localities for the application of management measures conducting on the level of lower planned units (departments) and thus lead to the successful planning and more efficient forest management. Obtained results at the researched area showed that a negative influence on the watering regime has groundwater level decreasing compared to the reference level because it directly affects available water for the plants. Based on multicriteria analysis methods, it was deduced that the most endangered parts are located at the edge, while this risk is much lower in the central part of the management unit. A combination of applied methods (geostatistics and multicriteria analysis) is of great importance for forestry management.
Lithobiont-dependent ionic composition in runoff water
Authors: Kidron Giora J. , Starinsky Abraham 
Published: August 2020

Abstract
Rock dwelling organisms (lithobionts) such as cyanobacteria (prokaryotes) and chlorolichens (eukaryotes) abound in the Negev Desert, where they cover almost all calcareous bedrocks and rock particles (cobbles, boulders). In a small limestone watershed in the Negev Highlands, cyanobacteria inhabit the south-facing (SF) bedrocks, epilithic lichens (accompanied by endolithic lichens) inhabit the north-facing (NF) bedrocks, while endolithic lichens cover most of the cobbles and boulders in both aspects. In order to study their contribution to runoff water, a pair of runoff plots was established on habitats with cyanobacteria, endolithic lichens, and epilithic lichens. Rain and runoff were collected during the hydrological year 2006/07, and the chemical composition (Ca, Mg, Na, K, Cl, SO4, HCO3, Si) of the rain and runoff water was analyzed. Several patterns were observed: (a) as indicated by Si, more dust accumulated on the bedrocks; (b) all substrates exhibited high amounts of Ca, and HCO3; (c) while SF-bedrocks showed enrichment in K, both bedrocks (and especially the NF bedrocks), as well as the NF boulders showed an enrichment in Mg. While the enrichment in Ca and HCO3 can be explained by the contribution of the limestone parent material, the enrichment in K and Mg can be explained by the contribution of the living lithobionts, with K being mainly contributed by the cyanobacteria and Mg mainly by the epilithic lichens. Ion enrichment may therefore be aspect-dependent, reflecting the lithobiont distribution within the drainage basin, partially explaining the enrichment in K and Mg previously recorded in runoff water from the Negev.
Three-dimensional numerical study of submerged spatial hydraulic jumps
Authors: Foda Ahmed S. , Imam Yehya E. , Bazaraa Abd Allah S. , Imam Emad H. 
Published: August 2020

Abstract
A three-dimensional numerical model was applied to simulate submerged spatial hydraulic jumps (SSHJ) downstream of a symmetric vent that discharges into a wider channel. Simulations were carried out for different aspect ratios of the vent, expansion ratios of vent width to downstream channel width, tailwater depth, and inlet Froude number. Depending on these factors, simulations indicated the formation of steady asymmetric SSHJ, oscillatory asymmetric SSHJ, and steady symmetric SSHJ, consistent with results of previous experimental studies. The model reproduced observed depth downstream of vent, jump length, and velocity profiles along channel centerline for steady symmetric SSHJ. For oscillatory asymmetric SSHJ, simulated oscillation frequencies had Strouhal numbers that varied with expansion ratio and ranged between 0.003 and 0.015. With piers downstream of the vent, oscillatory SSHJ continued to exhibit jet deflections when pier length was relatively short ( ≲ 0.2 of jump length) but became steady asymmetric for longer piers.
Against Universalism in Biosemiotic Theories
Authors: Rodríguez H. Claudio J. 
Published: August 2020

Abstract
The frontiers of biosemiotics are inconspicuously blurry. This is a feature and not a bug of the discipline in that it allows us to ask questions beyond certain boundaries, enriching both our knowledge beyond semiotic theories and the possibility of covering new ground through them. Yet, explanatory power should be something of a concern for biosemioticians looking to plant flags around different heights. The paths cleared by backwoodsmen should hold up to scrutiny, and in order for biosemioticians to examine these paths, some of the features of semiotic theory should work as reminders of what the aim of semiotic theory is.
This paper will explore one particular issue when it comes to building biosemiotic theories, namely, the idea that the semiotic comprises a universal and basal quality in a hierarchy of elements assumed to give rise to other, more complex things. The metatheoretical problem at its core will be defined as the unnecessary expansion of semiotic attributes in order to give them enough explanatory power to either provide semiotic theories of everything or give a semiotic basis to theories that do not, in principle, require it.
On the use of validated ocean models to investigate the evolution of primary productivity in the Levantine Sea
Authors: Kanj Malak , Fadel Ali 
Published: August 2020

Abstract
Marine ecosystems are vital natural resources that contribute to the global biogeochemical cycle, food, and energy production. In order to monitor and evaluate variations of different factors for decision making processes, validated ecosystem models were used in this study to analyze the evolution of different variables: temperature and salinity concentrations (from 1987 to 2014) and nitrate, phosphate, dissolved oxygen, chlorophyll concentrations, and phytoplankton biomass (from 1999 to 2014) in four sites (from 0 to 66 m depth) along the Levantine Sea: Lebanon, Turkey, Egypt and in the Open Sea. Principal component analysis and TRIX were then applied. Spatio-temporal analysis and PCA results showed that phytoplankton biomass is temporally affected by temperature and nutrients (in all stations) as well as salinity in some cases, in addition to its decrease with depth. TRIX analysis showed that all stations had higher primary productivity, in the first half of the year (January-May). Intense anthropogenic activities in Turkey and Egypt have altered the ecosystem’s stability and affected the phytoplankton biomass.
Quantitative Indicators of the Instantaneous Speed of a Ship’s Main Engine and its Usability in Assessing the Quality of the Combustion Process
Authors: Chybowski Leszek , Kazienko Damian 
Published: August 2020

Abstract
A graph of the changes in an engine’s operating speed can be used to assess the quality of the combustion in its cylinders. In this paper, the authors carried out tests on a Buckau-Wolf R8VD-136 ship engine, which was directly driving the propeller. This engine is owned by the Laboratory of Marine Engine Rooms at the Maritime University of Szczecin. For standard rotational speeds ranging from 200 to 280 rpm, with increments of 20 rpm, the authors measured the changes in the instantaneous speed for the engine’s normal operating conditions (reference graphs) as well as with one of the cylinders being out of operation. A no-combustion situation was successively introduced into each cylinder for each preset rotational speed. The obtained graphs of the instantaneous speed were then used to determine certain quantitative indicators, which the authors believe can provide information about the technical condition of the engine. The analysis concerned the averaged graphs of the speed under the conditions set for five consecutive engine operating cycles. The indicators that were calculated included the maximum difference in the speed over the engine’s full operating cycle, the uniformity of the engine speed and the differential speed area factor, the latter a term that has been proposed by the authors. The values of the individual indicators that were obtained from the reference graphs and the graphs with no combustion in one of the cylinders were compared. All indicators are sensitive to cylinder misfire. Conclusions were then drawn on the usefulness of these indicators in assessing the condition of an engine.
Analysis of Distortion Mechanisms Used in Rotary Steerable Systems
Authors: Ivanova Tatyana N. , Božek Pavol , Korshunov Aleksandr I. , Koretskiy Vladimir 
Published: August 2020

Abstract
Drilling with a rotary steerable system, the mechanical drilling speed increases by two times compared to drilling with a screw bottom-hole motor, which provides significant savings drilling-time. The effective length of the horizontal elbow increases, which enables to increase the production rate more than twice. It is found that in comparison with the bottom hole motor, rotary steerable system provides drilling smoother barrel, which reduces the risk of accidents to come out. The dependence between the type of the bent housing and the most rational fields of its application is revealed, recommendations on the choice of the rotary steerable system for various issues of directional drilling are developed.
Developing the Cognitive Abilities of Elderly People with the Use of IT Technologies: Presentation of the Project Assumptions and Description of the Research Concept
Authors: Kaźmierczak Jan , Bartnicka Joanna , Borgosz Gabriela , Ikem Benjamin , Jurasik Julia , Kręt Paulina , Pietrulińska Natalia , Radomski Maciej 
Published: August 2020

Abstract
The progress of digitization and the development of new technologies undoubtedly bring many benefits. However, they can also create or deepen problems related to the social exclusion of certain groups of people, such as the elderly, for whom modern technology is still largely unavailable, and even arouses a sense of uncertainty and fear (the so-called technophobia). The consequences of such a phenomenon become particularly evident in the situation of social isolation, whose unprecedented dimension is currently observed in the so-called COVID-19 pandemic era. In particular, the occurrence of the phenomenon of social exclusion combined with a pandemic situation has contributed to the development of the assumptions of the project entitled “Developing the cognitive capabilities of older people through information technology.” This project was developed by the INNOVATOR Student Science Club at the Faculty of Organization and Management of the Silesian University of Technology, and its goal is to develop a tool to support the acquisition of competences by seniors in the field of technological content, operation of electronic devices and the implementation of daily and routine activities using the Internet, e.g. shopping via the Internet or using tele advice services. The proposed tool is also to support the stimulation of the development of cognitive abilities of seniors using e.g. logical games. In the course of project implementation, a survey will be conducted in selected Nursing Homes, Retirement Homes, online forums for the elderly and through direct contact, the results of which will allow to learn the needs and possibilities of developing the abilities of the examined people, and assess the effectiveness of the designed tool in the process of transferring content and shaping competences. An element encouraging seniors to participate in the planned research will be their active participation in lectures and/or talks, workshops and discussions. The assumed result of the project will be to reduce the negative effects of isolation of seniors, improve their communication with their loved ones and reduce the generation gap. A complementary research task will be to develop a way to assess project results in qualitative and, where possible, quantitative dimensions.
Improving Performance Together: Twinning Partnership Between Medium and Low Performer Districts in Ethiopia
Authors: Argaw Mesele Damte , Desta Binyam Fekadu , Abebe Melkamu Getu , Mamo Elias , Gebru Tesfaye , Heyi Wubishet Kebede , Gela Chala , Bele Temesgen Ayehu 
Published: August 2020

Abstract
This article describes the United States Agency for International Development Transform: Primary Health Care Activity supported a twinning partnership strategy, which was implemented between districts (woredas) in the different performance categories. This study presents the details of the partnership and the result observed in health systems strengthening in Ethiopia. The twinning partnership strategy was implemented with six steps. The established relationship helps the health systems to build the skill and capacities of the health workforce at primary healthcare entities. Both partner woredas improved their performances through the established win-win relationship and institutionalized the characteristics of a learning organization.
Efficacy of Current Methods for Correction of Talipes Equinovarus in Patients with Central Hemiparesis
Authors: Ondar V. , Agaev A. , Ismailova S. , Prokopenko S. , Isaeva N. 
Published: August 2020

Abstract
The problem of physiological gait stereotype restoration in patients with post-stroke central hemiparesis remains relevant to this day. This is primarily associated with high risk of falls in this category of patients. At this point, there is a wide variety of methods related to exercise treatment and robotised correction or restoration of impaired gait against the background of post-stroke hemiparesis. At the same time, the problem of management of talipes equinovarus associated with this syndrome remains quite complex and not completely solved. We have analysed existing methods of talipes equinovarus correction with different levels of evidentiality.
Caduceus or Rod of Asclepius? Exploring Logos of University Teaching Hospitals in Nigeria
Authors: Kanmodi Kehinde Kazeem , Ogidan Ifeoluwa Oluwasolafunmi , Adegbile Oluwatobi Emmanuel , Kanmodi Precious Ayomide 
Published: August 2020

Abstract
Background: Historically, the Rod of Asclepius is considered as the correct symbol of Medicine. Unfortunately, many medical/health institutions in the world have erroneously interchanged the Rod of Asclepius symbol with erroneous symbols (e.g. Caduceus) to depict Medicine. This study aims to assess the official logos (i.e. institutional symbols) of university teaching hospitals in Nigeria and determine if these logos actually depict the true symbol of Medicine.
Methods: This study was a cross-sectional online survey of teaching hospitals in Nigeria on their official logos. A total of 40,556 operating hospitals and clinics in Nigeria were identified. After systematic screening, a total of 35 hospitals were identified as university teaching hospitals and used for the survey. Official information about the geopolitical zone, ownership and official logo of the selected hospitals was obtained (via online and offline search). Data collected was analysed using SPSS version 22 software.
Results: Out of the 35 surveyed university teaching hospitals, only 7 did not have snake(s) as part of their official logo. However, out of the remaining 28 hospitals that have snake(s) as part of their official logos, only 57.1% (16/28) of them have only one snake in their logo. Exactly half of the surveyed hospitals having logos with two entwined snakes (i.e. Caduceus) were owned by the federal government. Bivariate analysis showed that there exists statistically significant relationship between the geopolitical zone where a hospital is situated and the number of entwined snakes indicated in their official logo (p-value=0.034).
Conclusion: This study shows that the correct symbol of Medicine is not universally indicated in the official logos of the university teaching hospitals in Nigeria.
Test Stand for the Experimental Investigation of Turbochargers with 3D Printed Components
Authors: Andrearczyk Artur , Bagiński Paweł , Żywica Grzegorz 
Published: August 2020

Abstract
The paper discusses the universal test stand which allows determining the characteristics of turbochargers. Currently, there are works carried out in the world aimed to develop innovative fluid-flow machines, made partly with the use of rapid prototyping technology. This type of manufacturing technology allows reducing production time and costs in comparison to conventional methods of prototyping. This article also discusses start-up tests of the experimental test stand using a commercial turbocharger and the comparison between calculated and experimental results. In this paper, there are also described some modifications of the test stand, made prior to the start-up test, which were necessary to get more accurate characteristics of turbochargers. This work is an introduction to the investigation on turbomachines, whose elements were manufactured using the rapid prototyping technology.
Reconstruction of Turbomachines on the Basis of the Flow Structure Visual Diagnostics
Authors: Arsiri Vasyl , Kravchenko Oleg 
Published: August 2020

Abstract
The indicator of the quality of modern turbomachines is only the coefficient of efficiency, which characterizes the ratio of the useful work of compressors or fans to the energy expended on the drive. For the analysis of the quality of the motion, processes in flow parts, the values of resistances are used which are difficult to be considered as an indicator of the efficiency of dynamic processes. The report presents the results of visual diagnostics of the structure of flows during the movement in the elements of turbomachines, as well as options for improving the geometry of the flow parts - in the inlet pipes, impellers.
For the analysis of the efficiency of the motion of liquids and gases in flowing parts, a calculated index is proposed - the coefficient of hydraulic efficiency of dynamic processes. The joint use of two indicators - the efficiency of transformation of different types of energy (efficiency of turbomachines) and the efficiency of dynamic processes in flowing parts allows us to develop and to analyze the results of reconstruction of turbomachines. Reconstruction of turbomachines with the purpose of improving the geometry of the flow parts provides an increase in productivity of turbines, compressors, fans and pumps, while reducing the specific energy consumption for the processes of compression and transport of liquids and gases. Optimization of turbomachines flow parts based of flow structure visual diagnostics allows to reduce noise and vibration, as well as to solve other problems.
Thermodynamics Cycle of Gas-Cooled Fast Reactor
Authors: Polansky Jiri 
Published: August 2020

Abstract
This paper deals with the thermo-hydraulic aspect of gas cooled fast 4 generation reactor. The paper is focused on the comparison of direct and indirect strategy of thermodynamics cycle of helium cooled reactor from the thermodynamics and turbomachinary point of view. The analyses respect pressure looses at all major part of the equipment - reactor, heat exchanger, pipe lines, etc. The compressor and gas turbines efficiency are includes in calculation as well. The working fluid in primary circuit is helium. In the secondary circuit a mixture of helium and nitrogen is considered. The Cycle characteristic point and efficiency calculation reflects mixture properties of the real gas. Calculation point out the influence of mixture composition on the basic structural parameters of the turbines, compressor and heat exchangers. Thermodynamics cycle efficiency, specific heat input/output, heat flux and cycle work will be presented as characteristic parameters.
On the Modeling of Periodic Sandwich Structures with the Use of the Broken Line Hypothesis
Authors: Marczak Jakub 
Published: August 2020

Abstract
In this paper a dynamic analysis of sandwich plate with a certain periodic microstructure is considered. The initial system of governing equations is derived basing on the classic broken line hypothesis. As a result of transformations one can obtain a system of three differential equations of motion with periodic, highly oscillating and non-continuous coefficients. In order to derive a system of equations with constant coefficients tolerance averaging technique is applied. Eventually, in the calculation example a free vibration analysis of certain periodic plate strip is performed with the use of both the derived model and a FEM model. It can be observed that the consistency of obtained results is highly dependent on the calculation assumptions.
Dependence of defect concentration, optical and photocatalytic properties of β-Ni(OH)2/ZnO and NiO/ZnO composite powders on phase transformation
Authors: Suwanboon Sumetha , Klubnuan Sarunya , Homkaew Mukdawan , Amornpitoksuk Pongsaton 
Published: August 2020

Abstract
β-Ni(OH)2/ZnO composite powders were successfully synthesized by hydrothermal method at 180 °C for 15 h whereas NiO/ZnO composite powders formed after the as-prepared powders were calcined at 800 °C for 1 h in air. The X-ray diffractometer (XRD), scanning electron microscope (SEM), UV-Vis spectrophotometer were used to characterize the phase, particle shape as well as size and optical properties, respectively. In this system, it was found that ZnO is a major phase while β-Ni(OH)2 and NiO are a minor phases. The altered particle shape of ZnO was influenced by addition of Ni(CH3COO)2·6H2O whereas the particle shape of the minor phase was changed due to the calcination process. The optical band gap decreased when the amount of minor phase increased. For photocatalytic study, it was found that 6 mol% β-Ni(OH)2/ZnO composite powders exhibited the best decolorization of methylene blue aqueous solution.