bluuebunny/crossref_metadata_2025 huggingface dataset:
IMPACT OF COARSE AGGREGATE ON COMPRESSIVE STRENGTH OF CONCRETE
Authors: Quayson Jeriscot H. , Mustapha Zakari
Published: June 2020

Over one-third of the volume of concrete is occupied by coarse aggregate and any changes in coarse aggregate type can affect its strength and fracture properties. The paper examined the impact of coarse aggregates on compressive strength of concrete. Slump and compaction factor tests were conducted on the mixture of quartzite and crushed granite course aggregates, and quarry dust (fine aggregate). Nominal mix (1:2:3) was adopted and mix compositions were calculated by absolute weight method. Twelve (12) cubes (150x150mm) of each type of coarse aggregate were cast for 7, 14, 21, and 28 days to determine their compressive strengths. Quartzite was found to have the highest average compressive strength of 24.48N/mm2 with an average density of 2160kg/m3 , while compressive strength of crushed granite was 22.01N/mm2 with an average density of 2300kg/m3 on the 28 day of testing. Concrete made from granite had the highest workability, while concrete made from quartzite aggregate had the highest compressive strength. Densities and compressive strengths of the individual aggregates accounted for the variation in strengths of the concrete, due to differences in properties and strengths. In conclusion, the effect of any type of coarse aggregate on the compressive strength of concrete will be known and also enable contractors to determine the type of aggregate to be selected for a particular work.

Keywords: Compaction factor test; slump test; strength; workability.
Crystal - Rotator-I - Rotator-II Phase Transitions in the Mixtures of Alkanes
Authors: Mukherjee Prabir Kumar
Published: June 2020

Using the combination of Flory–Huggins theory of isotropic mixing and Landau theory, we discuss the crystal – rotator-I – rotator-II phase transitions in the binary mixture of alkanes. The influence of concentration on the order parameters and the transition temperatures is discussed. Theoretical results show the first order character of both the rotator-I to crystal and rotator-II to rotator-I phase transitions in the mixture of alkanes. A good agreement between theoretical and experimental results are presented in this paper.
La concepción antropológica en Orígenes de Alejandría: preexistencia del alma y su vinculación con la ἀποκατάστασις
Authors: Caram Gabriela
Published: June 2020

Orígenes de Alejandría fue un importante referente de la Iglesia oriental, destacado por su enorme saber. Se lo ubica y valora como el primer exégeta que hizo obra científica y como uno de los más grandes pensadores del cristianismo antiguo, ya que en todos los dominios fue capaz de marcar un momento decisivo para el pensamiento contemporáneo suyo y posterior. Maestro de Alejandría y de Cesarea, realizó la primera gran síntesis de teología especulativa y conocimiento de la realidad.En sus reflexiones, fue amplio en la introducción de elementos de la sabiduría de otras tradiciones, entre las que se cuentan la cristiana y judía, así como también la griega y bárbara. Todas estas tradiciones espirituales han coincidido en la afirmación de que el alma humana vive y persiste después de separarse del cuerpo, constituyéndose –nuevamente, según el alejandrino- en un cuerpo etéreo que abandona el cuerpo material. De este modo, alega la supervivencia del alma a la muerte física y la posibilidad de desplazarse en diferentes dimensiones o planos.En este caso, nos detendremos en estudiar, a partir de ciertos pasajes de su obra, aquellos contenidos que posibilitan la comprensión de los tópicos fundamentales para nuestra investigación en torno a los elementos antropológicos que aporta en sus trabajos. Se pondrá especial atención en las nociones de principio (ἀρχή, como concepto que abarca tanto la eternidad como el tiempo), preexistencia, el cuerpo etéreo de la preexistencia, sus transformaciones y su relación con la materia, el hombre en su totalidad y en su trascendencia, y finalmente su vinculación con la restauración final o ἀποκατάστασις.
Los hermanos erísticos del Eutidemo en las definiciones del Sofista
Authors: Villar Francisco
Published: June 2020

En este trabajo defenderé que los erísticos del Eutidemo se dedican a la sofística tal como esta es definida en el Sofista. Propondré que en tanto la quinta y la séptima definición se sirven del concepto de ἀντιλογικός, ambas son capaces de capturar el componente dialéctico y refutativo de la práctica erística. Preferiré indentificarlos con la séptima no sólo porque constituye la definición final del sofista, sino también porque esta incluye entre sus determinaciones el empleo engañoso de tal forma de argumentación, rasgo que se ajusta más a la erística que el cobro de dinero, elemento principal de la quinta.
La doble criticidad del Acontecimiento.
Authors: Esperon Juan Pablo
Published: June 2020

El presente artículo, tiene como objetivo mostrar que el giro copernicano (Kant) centrado en el Ego trascendental ha sido cuestionado y revisado críticamente por el giro lingüístico-hermenéutico contemporáneo al decir de Scannone.[1] Esta doble criticidad es posible a partir de la reinterpretación de las categorías esenciales de la metafísica moderna cuyo puntapié inicial puede situarse en el “otro comienzo” del pensar que produce Heidegger para la filosofía contemporánea. De este modo, la tesis que sostenemos en este artículo es que esta nueva racionalidad crítica se encuentra sintetizada en la noción de Acontecimiento heideggeriana. [1] Scannone, J. C.; “El nuevo pensamiento y el otro comienzo”: en Scannone, J. C. Comp.; Un nuevo pensamiento para otro mundo posible, Editorial de la Universidad Católica de Córdoba, Córdoba, 2010, p.10.
An assessment of leadership training needs of executive members of farmer-groups in Oyo State, Nigeria
Authors: Omotesho Kemi Funmilayo , Akinrinde Adeniyi Felix , Laaro Kafayat Adeshike , Olugbeja Joseph Oluwadare
Published: June 2020

The failure of farmers’ associations in Nigeria has been linked to leadership incompetency. In this study we investigated the leadership training needs of executives of farmers’ associations in Oyo State. Specifically, we examined the importance associated with the leadership roles by the executives, investigated their competence levels and identified the constraints they face in carrying out their roles. A two-stage sampling procedure was used to select 195 respondents on which an interview schedule was administered. The obtained data were analysed using descriptive statistics, the Borich’s Needs Assessment Model and the Pearson’s Product Moment Correlation. The respondents were middle-aged (52 years) with an average of 26 years farming experience and seven years of farmer-group membership. About 66 % had no formal education. Only 36.9 % of the groups originated out of felt needs, 44.1 % of the leaders emerged by selection, and the average group size was 28. Although the respondents affirmed the importance of all the 15 identified leadership roles, their competence level in 11 of the roles was low. Areas of training needs identified include resource mobilization and control, and the establishment of linkages with major stakeholders in agriculture. At P < 0.05 some personal and group characteristics of the respondents were related to their training needs. Inadequate knowledge of the roles and poor cooperation of members were the most severe constraints to effective leadership of the associations. The study concluded that the leaders of farmer-groups in the state had training needs which must be addressed to ensure the sustainability of the groups.
Stability of Picard operators under operator perturbations
Authors: Petruşel Adrian , Rus Ioan A.
Published: June 2020

In this paper we study the following problems: I. Let (M, d) be a complete metric space and f, g : M → M be two operators. We suppose that:

(a) f is a Picard operator with its unique fixed point x *
f
;

(b) there exists η > 0 such that d(f(x), g(x)) ≤ η, for every x ∈ M.

The problem consists in estimating d(g

n
(x), x

*

f
), for x ∈ M and n ∈ 𝕅*.

II. Let B be a Banach space and f, g : B → B be two operators. We suppose that f is a Picard operator. The problem is to find sufficient conditions which guarantee that f + g is a Picard operator.
On uniform exponential trisplitting for cocycles of linear operators in Banach spaces
Authors: Biriş Larisa Elena , Mihiţ Claudia Luminiţa , Ceauşu Traian , Popa Ioan-Lucian
Published: June 2020

The aim of this paper is to study the concept of uniform exponential trisplitting for skew-product semiflow in Banach spaces. This concept is a generalisation of the well-known concept of uniform exponential trichotomy. We obtain necessary and sufficient conditions for this concept of Datko’s type. a character-isation in terms of Lyapunov functions is provided. The results are obtained from the point of view of the projector families, i.e. invariant and strongly invariant.
Structural and Piezoelectric Characterization of Pr3+ Modified (1-x)Pb(Zr1-yTiy)O3 – xPb(Mn1/3Sb2/3)O3 Ceramic
Authors: Dumitru Alina Iulia , Velciu Georgeta , Pintea Jana , Patroi Delia , Marinescu Virgil , Clicinschi Florentina , Peter Ildiko
Published: June 2020

0.88Pb(Zr0.52Ti0.48)O3 – 0.12Pb(Mn1/3Sb2/3)O3 – 0,02 at%E piezoelectric ceramics, with E = Pr3+ were synthesized by using a conventional method, namely a solid state reaction technique. X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) were employed for the structural and microstructural investigations. Piezoelectric methods were used for the dielectric and piezoelectric properties determination. The results of XRD show a perovskite structure and XRD patterns, indexing on a tetragonal cell structure, was carried out for the most common phases. The SEM micrographs of the sintered compositions reveal a homogenous structure with a sharp or rounded grain boundary. The modified PZT ceramic presents still superior piezoelectric properties. Based on the results obtained, one can conclude that the analysed piezoelectric ceramics are useful for device applications.
Special Binding for Refractory Concretes
Authors: Stoian Elena Valentina , Ungureanu Dan Nicolae , Toma Florin , Colţa Alexandru Gabriel , Anculescu Daniel , Bratu Vasile , Angelescu Nicolae
Published: June 2020

The paper shows data related to coexistence of various binding systems, which could be present during the hardening of special concretes. It is taken into account the Ultra Low Aluminous Cement Concretes additivated with different materials (phosphates and mineral ultra dispersed powders - Condensed Silica Fume, Hydrated Alumina etc). In correlation to the pH-value, these substances can favour the forming of new binding systems besides the hydraulic binder (which is not important in this case). The new system is the coagulation binding form. The coagulation binding system has a very important role in the advanced compactness and in the increasing mechanical strengths of concrete structures.
Numerical Kinematical Analysis of the Articulated Quadrilateral Mechanism
Authors: Tătaru Mircea Bogdan , Tătaru Vladimir Dragoş
Published: June 2020

The paper presents a numerical method of kinematical analysis of the articulated quadrilateral mechanism. Starting from Euler’s relation concerning the distribution of speeds written in projections on the fixed reference system axes, a system of differential equations describing the movement of the mechanism was obtained. This system of differential equations was then solved using numerical integration methods and the variation with respect to time of the position kinematical parameters, of the velocities (the first order kinematical parameters), and of the accelerations (the second order kinematical parameters), was obtained. Matrix writing of the differential equations was used in order to make the differential equations set out in the paper easier to solve using the electronic computer.
Mathematical Method to Unfolding Couplings
Authors: Popa Carmen , Petre Ivona , Bratu Ruxandra-Elena
Published: June 2020

The purpose of this paper is to establish the intersection curves between cylinders, using Mathematica program. The equations curves which are inferred by mathematical methods are introduced in this program. This paper takes into discussion the case of four cylinders.
Avangarda (Anti)-Umană. Incursiune În Poezia Politică A Lui Paul Celan
Authors: Moroşan Ioana
Published: June 2020

This paper aims to analyse a part of Paul Celan's poetic discourse and study the way in which its political dimensions arise, with a particular focus on poems dedicated to Osip Mandelştam in the Nobody's Rose volume. For this purpose, a disjunction is made and justified between political poetry, or expressive discourse treating the political, and politically possessed poetry, discourse in service of ideology. Of particular interest is the social function assumed by such political poetry, triggered by the spreading of illness within the social corpus towards which the poet acts, in Ion Mureşan's conception, as a timely antibody.
Poezia visului real
Authors: Iulia-Maria Deaconu Ticărău
Published: June 2020

This article aims to review the anthology One Hundred and One Poems that includes a collection of poems and critical quotes selected by Alina Bako, who not only provides an overview of the lyrical universe created by Leonid Dimov, but also the critical tools needed for the specialized or non-specialized reader in order to step into the essence of Dimov’s creation. Thereby, the researcher contributes to the revival of the work of a poet who is still actual and valuable.
A Fi Evreu, A Fi Intelectual, A Fi Român Și Dunărean. Sionism Și Asimilare
Authors: Iulia-Maria Deaconu Ticărău
Published: June 2020

In this paper, I bring into discussion the concepts of Zionism and assimilation, as introduced in Mihail Sebastian’s novel For Two Thousand Years… Some critical points of view regarding these movements will be referred to in order to highlight the novelty of Sebastian’s approach and how he introduced these concepts within his fictional universe.
Instrumente Ale Poeticii Cognitive: O Aplicaţie Pe Lirica Lui Blaga
Authors: Pereş Paula
Published: June 2020

The aim of this paper is to offer a representation on how cognitive poetics can be used to analyse Lucian Blaga’s poetry. With the help of digital instruments designed for corpus linguistics, concordances of the term ‘fire’ are identified and classified, giving this cognitive process a material form, together with a hermeneutical perspective. Furthermore, an example of how the similarity in minds’ activity of a group, community, or culture regarding metaphors are englobed in a pattern, can also be remarked in this paper.
Numerical Approximation of The Weakly Damped Nonlinear Schrödinger Equation
Authors: Čiegis Raimondas , Pakenienė Violeta
Published: June 2020

In this paper we consider the one-dimensional nonlinear Schrödinger
equation. The equation includes an absorption term, and the solution is periodically
amplified in order to compensate the lose of the energy. The problem describes propa-
gation of a signal in optical fibers. In our previous work we proved that the well-known
Crank—Nicolson scheme is unconditionally unstable for this problem. We present in
this paper two finite difference approximations. The first one is given by a modified
Crank—Nicolson scheme and the second one is obtained by a splitting scheme. The
stability and convergence of these schemes are proved. The results of numerical exper-
iments are presented and discussed.
The Fast Solution of Periodic Integral and Pseudodifferential Equations by Gmres
Authors: Plato R. , Vainikko Gennadi
Published: June 2020

In this paper we consider GMRES to solve finite-dimensional approxi-
mations of a class of well-posed linear operator equations in Hilbert spaces. It is shown
that the speed of convergence is superlinear. As a consequence we have that GMRES
can be used as a fast solver of a fully discrete variant of the trigonometric Galerkin
equations associated with periodic integral equations.
On the Quasi-monotone Modified Method of Characteristics for Transport-diffusion Problems with Reactive Sources
Authors: Seaïd Mohammed
Published: June 2020

This is an attempt to construct a strong numerical method for transportdiffusion
equations with nonlinear reaction terms, which relies on the idea of the Modified
Method of Characteristics that is explicit but stable and is second-order accurate
in time. The method consists in convective-diffusive splitting of the equations along
the characteristics. The convective stage of the splitting is straightforwardly treated
by a quasi-monotone and conservative modified method of characteristics, while the
diffusive-reactive stage can be approximated by an explicit scheme with an extended
real stability interval. A numerical comparative study of the new method with Characteristics
Crank-Nicholson and Classical Characteristics Runge-Kutta schemes, which
are used in many transport-diffusion models, is carried out for several benchmark problems,
whose solutions represent relevant transport-diffusion-reaction features.
Experiments for transport-diffusion equations with linear and nonlinear reactive sources
demonstrate the ability of our new algorithm to better maintain the shape of the
solution in the presence of shocks and discontinuities.
Modified Three-point Difference Schemes of High-accuracy Order for Second Order Nonlinear Ordinary Differential Equations
Authors: Kutniv Myrosalv V.
Published: June 2020

This work discusses issues on the design and analysis of three-point difference schemes for the nonlinear boundary-value problem. A new effective implementation
of an exact three-point difference schemes on irregular grids in terms of homogeneous three-point difference schemes of a high-accuracy order is proposed.
Integral Equations of the Linear Sloshing in an Infinite Chute and Their Discretization
Authors: Galanin Mikhail M. , Nizkaya Tatiana V.
Published: June 2020

In this work we propose a new method for solving linear elliptic equations in an unbounded domain.
The method is based on the representation of the exact solution as the sum of two functions.
The former is the solution of some auxiliary problem and the latter can be found using the
Green formula. Using finite-difference schemes, this method has a quadratic order of accuracy
independent of the size of the computational domain, and in the 2D case requires O(N³) operations
to find the solution, where N³ is the number of nodes within the computational domain. In the 3D
case the method requires O(N^4) operations. Test computational examples showing the method's efficiency are given.
Approximation to the Solution of the System of Nonlinear Stochastic Differential Equations
Authors: Malyutin Victor
Published: June 2020

In this paper we consider the system of nonlinear stochastic differential equations. The solution of these equations is approximated by finite series of definite
integrals where every term of the series can be evaluated. To construct the approximation, the linearization technique and the technique for noncommuting matrices are used.
On Parallel Numerical Algorithms for Simulating Industrial Filtration Problems
Authors: Čiegis R. , Iliev O. , Lakdawala Z.
Published: June 2020

The performance of oil filters used in the automotive industry can be
significantly improved, especially when computer simulation is an essential component
of the design process. In this paper, we consider parallel numerical algorithms for
solving mathematical models describing the process of filtration, filtering solid particles
out of liquid oil. The Navier — Stokes — Brinkmann system of equations is used to
describe the laminar flow of incompressible isothermal oil. The space discretization
in the complicated filter geometry is based on the finite-volume method. Special care
is taken for an accurate approximation of the velocity and pressure on the interface
between the fluid and the porous media. The time discretization used here is a proper
modification of the fractional time step discretization (cf. Chorin scheme) of the Navier-
Stokes equations, where the Brinkmann term is considered in both the prediction and
the correction substeps.
A data decomposition method is used to develop a parallel algorithm, where the domain
is distributed among the processors by using a structured reference grid. The MPI
library is used to implement the data communication part of the algorithm. A theoretical
model is proposed for the estimation of the complexity of the given parallel
algorithm and a scalability analysis is done on the basis of this model. The results of
the computational experiments are presented, and the accuracy and efficiency of the
parallel algorithm is tested on real industrial geometries.
Robust discretization and a posteriori control for strongly oscillating solutions of the stationary Schrödinger equation
Authors: Dörfler Willy
Published: June 2020

We consider an example of a boundary value problem on an interval where the solution can
show strong oscillations. In order to solve such a problem numerically, standard methods
require meshes that resolve these oscillations and will thus need a prohibitively large
number of unknowns. In our approach we use special problem dependent basis functions in the
finite element method and provide an analysis for a priori and a posteriori bounds. In this
way we can construct an efficient approximation method for the solution of such boundary
value problems.
Determination of conversion factors for pine and spruce logs in stacks
Authors: Jodłowski Krzysztof , Witkowska Joanna
Published: June 2020

The aim of this article was to determine the conversion factors for stacked pine and spruce logs with a length of 3–6 m. To this end, we measured stacks and their logs of a total of 3322.12 steres of pine logs and 1468.46 steres of spruce logs. The conversion factors obtained in this work for pine logs of varying lengths negatively correlate with log length. However, statistically significant (p<0.05) differences were only observed between the longest logs as well as logs of 3 and 4 m in length. This may be due to various factors (mainly curvature, the presence of buttresses on butt logs and taper) influencing the stacking process of logs of increasing length. For logs with a length of 3, 4 and 5 m, the average value of the conversion factor increased with the log thickness class, although this dependence was not statistically significant. In the case of spruce raw material, the obtained conversion factors are similar to the values determined in previous studies. There was no significant correlation between the length of the log and its average diameter. A prerequisite for using conversion factors for large-sized logs is accurate stacking, where special attention should be paid to the parallel stacking of individual logs, aligning their front and back sides to be flush and forming the stack so that its top plane is parallel to the ground.
Challenges concerning terminology and methodology in forest sciences
Authors: Wodzicki Tomasz J.
Published: June 2020

Commonly used scientific terms and their specific meaning in the context of forest sciences and services were the focus of this article. Special attention was devoted to analyzing the meaning of ecological terminology such as “niche”, “homeostasis”, “natural” and “succession” in order to better understand problems related to the interaction between and within complex biological structures such as forest multi population ecosystems and the human population. Especially the role of Homo sapiens occupying an ecological niche in forest ecosystems, as well as in the Earth’s biosphere, formed the core in this discussion. One important challenge in terms of terminology and methodology concerns the considerable progress and interaction between achievements in the general sciences such as biology, physics, physiology, mathematics, sociology and economy as compared to forest sciences. Challenges are obviously accompanying the development in scientific terminology and are thus an important factor when conveying knowledge to the future doctors of forest sciences.
Colloquiality and stylistics of online alternative news media
Authors: Patráš Vladimír
Published: June 2020

The main line of the study is bound to the conditions, demonstrations and effects of colloquiality (colloquialization) parameter that has been applied in the current electronic media communication sphere. Colloquiality as a non-verbal, structural and compositional attribute of a piece of communication is primarily present in the open, semi- and non-official communication contacts with direct, immediate involvement of their participants. In traditional print journalism built on the verified principles of printedness/ writtenness, colloquiality occurs as a secondary, accompanying attribute of the media communication pieces. Regardless of the genre affiliation of the newspaper products, it helps perform their, e.g., documentary, persuasive, captivating, characterizing, relieving or aesthetic functions. Apart from the parameter of printedness, both mainstream and alternative (complementary) online media generally calculate upon the advanced options of the visual code systems. Thus, language-based online newspapers are easily supplemented with simultaneous, additional, or substitutional means and procedures of cinematographic origin, e.g., a surprising choice, dynamic edition, purpose-made superposition of the text, audio and video sequences being applied through hyperlinking, audiovisual effects, etc. Besides, accompanying dialogization and consequent de-officialization of online newspapers are changing conventional characteristics of the journalistic style. The expanding zone of colloquiality loosens the standards of codified language in written/printed communication. Boundaries between the varieties in the framework of language stratification are already easily penetrable. The material base and argument platform of the study consist of author texts published in the Slovak online alternative news media.
Analysis of Possibility Limiting the Time of Test Injector in Diesel Engine Using Factory Test Bench Producers of these Elements
Authors: Bąk Witold , Wojnar Grzegorz
Published: June 2020

Regeneration of parts is the most correct form of use of worn out components and contributes, among others, to reduce CO2 emissions. In the case of elements of fuel injector systems, very high precision is required and such regeneration should be carried out using the original parts. It also requires testing on the original testing stands of these manufacturers, which very often characterized by the fact that it is not possible to perform a short test, which means that it is only possible to perform a time-consuming comprehensive test. An unquestionable advantage in some cases would be the possibility of preliminary verification of the correct operation of the regenerated subassembly without the need for a full time-consuming test. In the present situation, only after completing a time-consuming comprehensive test of the diagnosed element of the injection system, it is often necessary to carry out its disassembly, replacement or correction of one of the components and reassembly with the next time-consuming test. In the case of low unemployment in the labour market, this is extremely unfavourable, and it is often not possible to organize work in such a way that the diagnostic test of the subassembly takes place without the participation of an employee. On the basis of the analyses presented in this article, carried out in the research and development department in company whose employee is one of the co-authors, it can be stated that in the current situation on the labour market where skilled workers are required to work and for the development of science is the most purposeful recognition of the possibility of using vibroacoustic signals to shorten time of tests, which with a high probability may end in a negative result. The preliminary analysis carried out, show that limitation of diagnostic time can be over 35%.
Modelling Method of Dynamic Characteristics of Marine Thin-Walled Structure
Authors: Van Doan Do , Szeleziński Adam , Murawski Lech , Muc Adam
Published: June 2020

Thin-walled structures are very popular in industries, especially in the field of shipbuilding. There are many types of equipment and structures of ships, which are made up of thin-walled structures such as hull, deck and superstructure. Therefore, the analysis and understanding of the static and dynamic characteristics of a thin-walled structure are very important. In this article, we focus on vibration analysis of a typical thin-walled structure-rectangular plate, a basic structure of the hull. Vibration analysis of a rectangular thin plate is conducted by two methods: numerical modelling method of the finite element on Patran-Nastran software platform and experimental method implemented in the laboratory of Gdynia Maritime University. Thin rectangular plate is fixed one end by four clamping plates and is modelled with finite elements and different meshing densities. The numerical model of thin rectangular plate is divided into four cases. Case 1, thin rectangular plate, and clamping plates are modelled with two-dimensional elements. Case 2, the rectangular thin plate is modelled with two-dimensional elements; the clamping plates are modelled with three-dimensional elements. Case 3, both the rectangular thin plate and clamping plates are modelled with three-dimensional elements. Case 4, the rectangular thin plate, and clamping plates are modelled with three-dimensional elements with larger mesh density to increase the accuracy of the calculation results. After that, the results of vibration analysis according to the numerical modelling method on Patran-Nastran software platform for these cases were compared with the measurement results. From there, assess the accuracy of analysis results of selected numerical model methods and the ability to widely apply this numerical model method to other marine structures.
Distributions of Hydrodynamic Pressure in the Gap of Slide Journal Bearing Lubricated with Ferro-Oil
Authors: Frycz Marcin
Published: June 2020

This research work is part of a broader comprehensive issue, which is the analysis of flow and operating parameters of journal slide bearings lubricated with ferro-oil. In this article, the author presents only the main assumptions and essential transformations of the analytical and numerical model for determining the pressure distributions in the gap of a slide journal bearing lubricated with ferro-oil. It is cardinal that the rheological and magnetic values of ferro-oil parameters adopted in numerical calculations are based on the results of actual values obtained in the author’s earlier research work. There are presented the pressure distributions by abovementioned method in the article for cases of bearings lubricated with ferro-oils with different concentration of magnetic particles. The obtained results are shown in the form of a set of four complementary characteristics of the dimensionless pressure distributions. First and main of them are the calculations for classical Newtonian lubrication but they take into account the influence of the magnetic field on the distributions. The next of the presented characteristics are so-called “corrections” of pressure distribution values, taking into account as follows: effects of changes in ferro-oil viscosity related to temperature changes, impacts of ferro-oil viscosity changes related to pressure changes and the effect of non-oil properties of the lubricant. The article includes a qualitative and quantitative analysis of the obtained results as well as observations and conclusions are presented in it.
The Development of the World Fleet of Electric Vehicles in Years 2010–2017 with Emphasis on Fuel-Cell Vehicles
Authors: Gis Wojciech , Menes Maciej
Published: June 2020

The article discusses the development of the world EV fleet in years 2010-2017. Estimates of fleet of plug-in hybrid electric vehicles (PHEV) and BEV in the world are presented. The total number of PHEVs registered in the world in 2016 was roughly 800 thousand (650 thousand in EU). Despite the fact that the sale of electric vehicles has increased considerably in recent years, in particular over 1.1 million in 2017, and also hybrid electric vehicles (PHEV) to approx. 760 thousand in 2017. The article also discusses the development of the electric vehicles market and annual new registrations of vehicles in a breakdown into respective countries. China is the definite leader in this area. In 2017 there were almost twice more BEVs registered in China than in the US and EU together. While the increase in the sale of BEVs in years 2016-2017 in the EU and the US accounted for approx. 50%, it came to over 90% in China. Among eight top worldwide BEV producers, there are four Chinese manufacturers. In the analysed 2017, there were slightly more than 7 thousand of hydrogen-fuelled passenger cars (FCEV) in use, with over 3,500 in the US, 2,300 in Japan and approx. 1,200 in Europe, and several hundred hydrogen-fuelled buses and several dozen hydrogen-fuelled trucks. The article also addresses the development of hydrogen refuelling stations (HRS) in recent years in different countries in the world, bearing in mind that the quantitative development of the hydrogen-fuelled car fleet is strongly associated with the number of hydrogen refuelling stations.
Energy Balance of a Vehicle Equipped with Hybrid Propulsion System Fuelled with Alternative Fuels
Authors: Karczewski Mirosław , Szczęch Leszek , Polak Filip
Published: June 2020

Article presents the energetic balance of small-unmanned vehicle hybrid power transmission. The vehicle equipped with serial hybrid transmission consisted of electric engines connected to the battery pack and small Diesel power generator. In mentioned construction, battery is used as energy buffer and combustion engine is used more as emergency power supply, and is turned on when battery is depleted. In other condition, power generator can be turned off, without reducing power of transmission parameters, except its range. Vehicles with hybrid drive are very common chosen vehicles by users. More and more often, we also talk about searching for replacement fuels for internal combustion engines, so also for those with hybrid drive. The research was carried out on an unmanned land platform equipped with a hybrid propulsion system supplied as standard with Diesel oil. The article presents the problems of comparing the efficiency of a hybrid vehicle fuelled with Diesel oil, but also with alternative fuels based on kerosene and other components. For test, three types of fuels were used, standard Diesel oil, F-34 and with experimental mixture of Jet A-1 fuel with 10% of 2-ethylhexanol. Energy used for charging of the battery, from tank-to-wheel, was calculated. This also enables to calculate total efficiency of such hybrid power transmission, powered with different fuels.
The Influence of Cutting Parameters on Surface Topography During Turning Marine Pump Shafts
Authors: Labuda Wojciech
Published: June 2020

One of the greatest problems of modern production techniques is the achievement of an appropriate quality at minimal costs and accompanied by the production efficiency increase. Therefore, while designing the production process. The technology used should have a considerable influence on the durability and reliability of machine parts to be produced. During finish treatment, the final dimensions as well as functional properties are imparted to a given element by application of proper treatment type. The engineer has a range of production techniques to choose for the proper surface layer formation. Conventional turning machines belong to the basic equipment of ships, because in sea conditions, they enable the execution of a spare part or carrying out the necessary operations in the process of their regeneration. The use of modern cutting tools makes it possible to obtain a surface with low values of surface roughness parameters. The use of new generation cutting inserts on conventional lathes can cause problems for operators. The lack of the ability to ensure proper of treatment condition and setting errors of cutting tools contribute to the damage of the cutting insert or the surface of the workpiece. The article presents the results of influence of different cutting parameters on surface topography during turning process of stainless steel. A shaft made of 304L stainless steel was used for the research. The cutting process was carried out on a universal TUM 25B x 500 centre lathes. During the turning the following machining parameters were used: cutting speed Vc [m/min], feed f [mm/rev] and depth of cut ap [mm].The turning process was conducted by a cutting tool with CCGT 09T302 UM, CCGT 09T304 UM and CCGT 09T308 UM inserts. Measurement of surface topography was carried out by T8000 profilometer.
Modelling of Helicopter Main Rotor Aerodynamic Loads in Manoeuvres
Authors: Kowaleczko Grzegorz , Leśniczak Andrzej
Published: June 2020

The article discusses the method of modelling of the helicopter main rotor aerodynamic loads during steady state flight and manoeuvres. The ability to determine these loads was created by taking into account the motion of each blade relative to the hinges and was a result of the applied method of aerodynamic loads calculating. The first part of the work discusses the basic relationships that were used to build the mathematical model of helicopter flight. The focus was also on the method of calculating of the aerodynamic forces generated by the rotor blades. The results of simulations dedicated to the “jump to hover” manoeuvre were discussed, showing the possibilities of analysing aerodynamic loads occurring in unsteady flights. The main rotor is considered separately in an “autonomous” way and treated as a source of averaged forces and moments transferred to the hub. The motion of individual blades is neglected, and their aerodynamic characteristics are radically simplified. The motion of individual blades is neglected, and their aerodynamic characteristics are radically simplified. This can lead to significant errors when attempting to model dynamic helicopter manoeuvres. The more complex model of helicopter dynamics is discussed.
The lost chance of public education. Fatal heritage, escapism of the elites, sparks of hope
Authors: Kwieciński Zbigniew
Published: June 2020

The article raises the question of the causes of the public education crisis, both the crisis in recent past and that conditioned by several centuries of Poland’s past. The position of Adam Podgórecki on the subject of comprehensive analyzes of Polish society is particularly important. It combines two positions. He believes that the causes of Polish systemic crises are the experiences of post-totalitarianism and specific Polish defects persisted for several centuries. The author of the article negatively assesses the possibility of overcoming the crisis of public education by academic elites, which are responsible for the collapse of universities and the crisis of higher education. Common beliefs about public education have turned out to be illusions. The author sees the hopes of improving the state of public education in resistance to the destruction of democracy and to the strong ideological and political pressure. Openness to Europe and the world, which Poles do not give away, also gives hope.
Education under the baobab tree. About reforming education in the Republic of Kenya
Authors: Czerepaniak-Walczak Maria
Published: June 2020

In the text, on the background of a brief presentation of the political and demographic specifics of the Republic of Kenya, the education system in this country is discussed, with particular emphasis on its structure following the latest reform. The premises and assumptions of the reform of the school system and teachers’ education are briefly outlined. Current changes at universities are also discussed.
How to make research in school?-some examples off applying qualitative and mixed research strategies in analyzing of school environment on the basis of discussion about research strategies
Authors: Karkowska Magda
Published: June 2020

Content presented in this article is focused on the reflection of the factors determining the choice of research strategy in the analysis of school environment. Some of the elements to be examined refer to the structural and functional model of a school, others to the interpretative model. As the assumptions about the nature of school reality are completely different within these models, depending on how the school is perceived, there are different ways of designing and conducting research. It is arguable whether derived from a structural and functional model of school (the school as an environment education, positivist paradigm) only quantitative analysis are justified, and after the adoption of the interactive model (the school as a system of socio-cultural, interpretative paradigm) only qualitative research should be conducted? The choice, at the first glance, quite obvious is a matter of more complex, because the strategy of research procedure also depends on some another factors: the order in which the study is carried out, the subject and the scope of the analysis, the experience of the researcher and to some extent, to the fact who are beneficients of the results. In the first part of this article author is trying to deal with these relationships, in the second part, there are presented a few examples of analysis when using qualitative methods or strategies. Most of them are realized within the model of so-called mixed research. They are only some examples presented and they should be understood as exemplifications, not in –depth exploration. Described problems might be explained and explored in the future using other methods and techniques, as well as combining them.
Beyond the Infantilization of Higher Education: Preparing students to live in an (un)safe society
Authors: Babicka-Wirkus Anna
Published: June 2020

The article deals with the problem of the infantilization of students, which takes place at universities. The starting point is the thesis that contemporary education at higher levels does not prepare students for the development of critical thinking and does not provide the skills to deal with problematic situations typical of global society. Instead, it approves and implements mechanisms leading to the infantilization of adults, such as: censorship, caution, language medicalization and microaggression. In the text I analyze these dangerous phenomena and indicate the consequences that they bring, not only for the development of the institution itself, but also its autonomy, and above all the students academic growth.
Performing Individualism. Two Tendencies Dismantling War Imagery in Croatian and Serbian Historical Novels of the 1960s
Authors: Czerwiński Maciej
Published: June 2020

The article aims at addressing the question of representations of World War Two in Croatian and Serbian literature that were subversive in the sense that they queried the legend not simply by rejecting communism and affirming nationalism, but by emphasizing the uncertainty and sensibility of the human beings, a typical modern reaction to violence and, in general, modernist topoi. In this article I will focus on modernist novelistic representations of the 1960s in which the uncertainty and instability of collective warrants are foregrounded. As a result a subversive meaning is produced which contradicts not only communism and revolution but more generally war as such, including the universal features of war such as confronting loneliness, love as an expression of an individual rather than a collective sense of existence, and the impossibility of a valid representation of past events.
The Right, Procedures and Reasons of the Withdrawal of States from International Organizations
Authors: Rashica Viona
Published: June 2020

Withdrawal is an act by which a member state of an international organization willingly terminates its membership. The right to withdraw from international organizations is explicitly mentioned in the constitutions of most of them and the circumstances regarding to the right of withdrawal vary depending on the organization. The purpose of this paper is to explain the right and procedures of withdrawal, and the reasons that result with the will of states to withdraw from international organizations. For the realization of this research are used qualitative methods, based on the bibliography that is related to international organizations, with special emphasis with the right and procedures of the withdrawal of states from international organizations. Furthermore, some informations are also collected from the credible internet sources, which have valuable data about the withdrawals of states from international organizations and the reasons that result with such decisions. The results of the research have shown that since the appearance of international organizations until today, there were and there are decisions of states to withdraw from international organizations, coming from the reluctance of states to hand over to international organizations parts of their sovereignty. The conclusions of this paper aim to increase knowledge about the real meaning of the processes of withdrawals of states from international organizations.
Methods of Protection of the Property Right in the Legal System of Republic of North Macedonia
Authors: Zendeli Emine
Published: June 2020

The article aims to analyze the legal norms that regulate the protection of the property right in the legal system of the Republic of Macedonia. In most cases, the protection of property right is realized through suits; however, our legal system provides for the possibility that the protection of property right can also be realized through the registration of immovable property rights in the respective Public Registries.

Given the fact that in the Republic of North Macedonia the normative regulation of property suits is not contained in a single normative act, but rather extends to several such acts, the article, based on the practice of the high courts, seeks to analyze the legal cases related to property rights that qualify as rights similar to property rights, but which enjoy legal protection provided by law.

The article will mainly elaborate on the basic provisions on property protection suits contained in the Law on Ownership and other Real Rights (2001). However, in this context, the provisions on property protection that are contained in the Law on Real Estate Cadastre (2008), the Law on Contentious Procedure (2005), the Law on Securing of Claims (2007), the Law on Construction Land (2008), etc., will also be taken into consideration.
Multiple Eruptive Dermatofibromas in Patient with Systemic Lupus Erythematosus
Authors: Janc Monika , Ristić Gorica , Vasić Nenad , Petrov Nenad , Sekulović Lidija Kandolf
Published: June 2020

Introduction. Multiple eruptive dermatofibromas are described in association with different immune-mediated conditions like SLE, pemphigus, myasthenia gravis, HIV infection, organ transplantation, acute myeloid leukemia, ulcerative colitis, atopic dermatitis and immunosuppressive therapy. Case Report. A forty-five year-old woman presented at our Department with over 20 dermatofibromas on her trunk and extremities developed spontaneously over the last 3 years, out of which more than 10 lesions developed over the previous year. The patient was diagnosed with systemic lupus erythematosus before the onset of lesions and was treated with different immunomodulatory agents (corticosteroids, methotrexate, antimalarials, azathioprine, belimumab, anti IL-6 antibody). Dermoscopy of different lesions revealed different dermatoscopic patterns without pattern predominance. A biopsy specimen of one lesion confirmed the diagnosis. Conclusion. There are few cases reports describing a possible link between systemic lupus erythematosus and multiple dermatofibromas. The mechanism is still unknown but is believed to be due to the altered immunity in immune-mediated diseases.