Wyniki wyszukiwania dla: HYBRID SYSTEMS - MOST Wiedzy

Wyszukiwarka

Wyniki wyszukiwania dla: HYBRID SYSTEMS

Wyniki wyszukiwania dla: HYBRID SYSTEMS

  • THERMAL ANALYSIS AND DESIGN OF HYBRID MICROCHANNEL -MICROJET TEST PROBE

    Publikacja

    Accurate control of cooling parameters is required in ever wider range of technical applications. It is known that reducing the flow hydraulic diameter to an increase in the economy of cooling and improves its quality (Mikielewicz and Muszyński 2009). Present study describes research results related to the design and construction of the test stand for hybrid microjet- microchannel cooling modules study, which may be applied in...

  • The influence of core material on strength properties of hybrid sandwich panels

    Publikacja

    - Rok 2014

    Along with high prices of fuels and more restrictive safety and environmental regulations (including environment protection) increased interest in sandwich structures is being observed. One of the solution having growing application potential is steel sandwich panel. The construction consist of very thin steel plates (about 2mm) and stiffeners between them. The main advantage of using such solution is very high strength to weight...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • The Hybrid Fuzzy - SOEKS Approach to the Polish Internet Mortgage Market

    The paper presents the hybrid fuzzy- SOEKS approach to the Polish Internet mortgage market, which is treated as an example of a fast changing market. Firstly, the market and market problems are described. Then, the first approach to the market problems is presented: the complete fuzzy model which was built basing on the rules. The fuzzy model is presented on one real data case. Next, the new approach, called Set of Experience Knowledge...

    Pełny tekst do pobrania w portalu

  • Hybrid Modulation for Modular Voltage Source Inverters with Coupled Reactors

    This paper proposes and discusses a concept of a hybrid modulation for the control of modular voltage source inverters with coupled reactors. The use of coupled reactors as the integrating elements leads to significant reduction in the size and weight of the circuit. The proposed modulation combines novel coarsely quantized pulse amplitude modulation (CQ-PAM) and innovative space-vector pulse width modulation (SVPWM). The former...

    Pełny tekst do pobrania w portalu

  • Ranking of Generation Source Locations by a Hybrid Multi-Criteria Method

    The paper presents a ranking of the locations of eight renewable energy sources (RES) made using a hybrid multi-criteria analysis method. The method is a combination of the analytical hierarchical process (AHP) method and numerical taxonomy. The considered generating sources, i.e. solar plants, biogas plants, and wind farms are sources that will significantly contribute to implementing the provisions of the energy and climate package...

    Pełny tekst do pobrania w portalu

  • Heat transfer characteristics of hybrid microjet – Microchannel cooling module

    The paper presents experimental investigation of heat transfer intensification in a microjet–microchannel cooling module. Applied technology takes benefits from two very attractive heat removal techniques. When jets are impinging on the surface, they have a very high kinetic energy at the stagnation point, also in microchannels boundary layer is very thin allowing to obtain very high heat fluxes. Main objective of this paper was...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • A simplified model of 3-D pipe system conveying flowing liquid

    Publikacja

    The paper presents a model reduction technique of a 3-D pipe system with flowing liquid. In the analysis and design of control (mechatronic) systems it is useful to work with simple, low order models. A hybrid reduced order model is proposed. The system model consists of two parts, the modal model and the finite element model.

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Hybrid SONIC: joint feedforward–feedback narrowband interference canceler

    SONIC (self-optimizing narrowband interference canceler) is an acronym of a recently proposed active noise control algorithm with interesting adaptivity and robustness properties. SONIC is a purely feedback controller, capable of rejecting nonstationary sinusoidal disturbances (with time-varying amplitude and/or frequency) in the presence of plant (secondary path) uncertainty. We show that although SONIC can work reliably without...

    Pełny tekst do pobrania w portalu

  • Heat transfer characteristics of hybrid microjet -microchannel cooling module

    Publikacja

    The paper presents the experimental investigation of heat transfer intensification in a microjet- microchannel cooling module. Applied technology takes benefits from two very attractive heat removal techniques. When jets are impinging on the surface, they have a very high kinetic energy at the stagnation point, also in microchannels boundary layer is very thin allowing to obtain very high heat fluxes. Main objective of this paper...

  • Determining the operational loads of the hybrid metalworking machines drive

    Publikacja
    • V. Skeeba
    • P. Skeeba

    - IOP Conference Series: Earth and Environmental Science - Rok 2019

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Reliability of quality forecast for hybrid metal-working machinery

    Publikacja
    • V. Yu
    • V. Ivancivsky

    - IOP Conference Series: Earth and Environmental Science - Rok 2018

    Pełny tekst do pobrania w serwisie zewnętrznym

  • A new magnetic-hybrid photoreactor for photocatalytic water disinfection

    Publikacja

    - Chemical and Process Engineering - Rok 2023

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Hybrid excited electric machine with axial flux bridges

    Publikacja
    • P. Paplicki
    • R. Palka
    • M. Wardach
    • P. Prajzendanc
    • M. Evelina

    - INTERNATIONAL JOURNAL OF APPLIED ELECTROMAGNETICS AND MECHANICS - Rok 2019

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Application of hybrid signals processors to speech and hearing aids

    Publikacja

    - Rok 2005

    Dzięki postępowi w technice Cyfrowych Procesorów Sygnałowych (ang. DSP) stało się możliwe budowanie miniaturowych protez słuchu i mowy. Mimo niewielkich wymiarów procesory te są w stanie wykonywać złożone algorytmy. Ich dodatkową zaletą jest łatwość zmiany oprogramowania, a co za tym idzie łatwość zmiany dziedziny zastosowań. W pracy skupiono się na zagadnieniach związanych z projektowanie i implementacją algorytmów mających zastosowanie...

  • The control of the contactless hybrid short-cicruit current limiter

    Publikacja

    Przedstawiono podstawowe zasady sterowania praca bezstykowego ogranicznika prądów zwarciowych. Dokonano analizy czynników wpływających na poprawną pracę bezstykowego ohranicznik aprądów zwarciowych ze szczególnym uwzględnieniem poprawy jakosci energii elektrycznej poprzez eliminację zapadów napiecia.

  • Manufacturing and and properties of hybrid SiCp-Cf/Al composite.

    Publikacja

    - Rok 2004

    Przedstawiono nowy kompozyt hybrydowy o zbrojeniu preformą z ciągłego włókna węglowego 3D nasycaną ciekłym stopem Al.-Si7Mg wzmocnionym ziarnami SiCp (15%vol.) za pomocą infiltracji pod ciśnieniem. Peforma szklana odgrywała rolę filtra dla ciekłego kompozytu aluminiowego.

  • Hybrid System for a Person Tracking in Harsh Indoor Environments

    In the article, the prototype of a system for a person tracking in a harsh indoor environment, especially when no other commercially available radiolocalization system can be used, was briefly described. The prototype realizes the data fusion, i.e. combines data from inertial and environmental sensors and radio distance measurements to estimate the position of a moving person. It is worth noting that the concept and practical realization...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Thermal Analysis Of Hybrid Microchannel-Microjet Heat Exchanger

    Publikacja

    The paper presents the numerical investigation of a microjet- microchannel cooling module. In which microjets of water are impinging into the microchannels and forming a liquid film on the impingement surface. Applied technology takes benefits from two very attractive heat removal techniques. When laminar jets are impinging on the surface have a very high kinetic energy at the stagnation point, also in microchannels boundary layer...

  • Hybrid biobattery based on arylated carbon nanotubes and laccase

    Publikacja

    - BIOELECTROCHEMISTRY - Rok 2011

    Jednościenne nanorurki węglowe modyfikowano resztami antracenu i antrachinonu Otrzymany materiał posłużył do modyfikacji elektrody węglowej w celu jej zastosowania do redukcji tlenu w bioogniwie paliwowym. Nanorurki z aromatycznymi grupami zwiększyły powierzchnię elektrody oraz przyczyniły się do zwiększenia bezpośredniego przeniesienia elektronów. Grupy arylowe mogą wnikać do hydrofobowej kieszeni enzymu, w której znajduje się...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Hybrid biobateryy based on arylated carbon nanotubes and laccase

    Publikacja

    - BIOELECTROCHEMISTRY - Rok 2012

    Single-walled carbon nanotubes (SWCNT) were covalently modified with antracene and antraquinone and used for the construction of cathodes for biocatalytic reduction od dioxygen. The nanotubes with aromatic groups casted onto the electrode increased the working surface of the electrode and enabled efficient direct electron tarnsfer (DET) between the enzyme and the electrode. the aryl groups enter the hydrophobic pocket of the T1...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Autonomic hybrid photovoltaic installations supported by thermoelectric generators

    Publikacja

    - Rok 2012

    Generatory termoelektryczne są urządzeniami dokonującymi bezpośredniej konwersji energii cieplnej na elektryczną.W ostatnich latach obserwuje się dynamiczny rozwój ich technologii, konstrukcji oraz obszarów zastosowań. Ponieważ ich sprawności systematycznie rosną, zatem w niektórych realizacjach celowe staje się ich zastosowanie do wspomagania autonomicznych hybrydowych instalacji fotowoltaicznych.W artykule dokonano przeglądu...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Experimental Research on the Energy Efficiency of a Parallel Hybrid Drive for an Inland Ship

    The growing requirements for limiting the negative impact of all modes of transport on the natural environment mean that clean technologies are becoming more and more important. The global trend of e-mobility also applies to sea and inland water transport. This article presents the results of experimental tests carried out on a life-size, parallel diesel-electric hybrid propulsion system. The eciency of the propulsion system was...

    Pełny tekst do pobrania w portalu

  • Hybrid Laboratory of Radio Communication With Online Simulators and Remote Access

    Contribution: Two toolsets for the remote teaching of radio communication laboratory classes: 1) online simulators for individual work of students and 2) a remote access system to laboratory workstations for group work. Initial assumptions and method of implementation of both tools are presented. Background: The COVID-19 pandemic has forced a change in teaching at all levels of education. The specificity of practical classes, such...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Highly antifouling polymer-nanoparticle-nanoparticle/polymer hybrid membranes

    Publikacja
    • V. Vatanpour
    • M. Jouyandeh
    • S. S. Mousavi Khadem
    • S. Paziresh
    • A. Dehghan
    • M. Ganjali
    • H. Moradi
    • S. Mirsadeghi
    • A. Badiei
    • M. T. Munir... i 7 innych

    - SCIENCE OF THE TOTAL ENVIRONMENT - Rok 2022

    We introduce highly antifouling Polymer-Nanoparticle-Nanoparticle/Polymer (PNNP) hybrid membranes as multi-functional materials for versatile purification of wastewater. Nitrogen-rich polyethylenimine (PEI)-functionalized halloysite nanotube (HNT-SiO2-PEI) nanoparticles were developed and embedded in polyvinyl chloride (PVC) membranes for protein and dye filtration. Bulk and surface characteristics of the resulting HNT-SiO2-PEI...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • A hybrid model of flooding of the ro-ro ships in damaged conditions

    The paper presents some results on investigations concerning development of a hybrid model for assessment of performance of the ro‐ro ships in damaged conditions. The model is devoted towards assessing the performance of the damaged ro‐ro ships at the preliminary stage of design. The key problems associated with preparing of such the model are associated with working out a method of assessment of the damaged roro ships performance,...

    Pełny tekst do pobrania w portalu

  • Exfoliated graphite with spinel oxide as an effective hybrid electrocatalyst for water splitting

    Publikacja
    • M. Skorupska
    • K. Kowalska
    • M. Tyc
    • A. Ilnicka
    • M. Szkoda
    • J. P. Lukaszewicz

    - RSC Advances - Rok 2023

    The aim of the conducted research was to develop hybrid nanostructures formed from MnCo2O4 and exfoliated graphite. Carbon added during the synthesis allowed for obtaining a well-distributed MnCo2O4 particle size with exposed active sites contributing to the increased electric conductivity. The influence of the weight ratios of carbon to a catalyst for hydrogen and oxygen evolution reactions was investigated. The new bifunctional...

    Pełny tekst do pobrania w portalu

  • CFGFRPT Piles with a Circular Cross-Section and their Application in Offshore Structures

    The possibilities of using concrete piles in a polymer composite reinforced with glass fibres in offshore facilities were shown. Laboratory tests of CFGFRPT type piles compressed axially and in eccentric compression for the analysis of CFGFRPT piles were used. Methods of analysis of dynamic systems for mathematical modelling of the displacement of the hammer in the pile driving process were applied. The possibilities of combining...

    Pełny tekst do pobrania w portalu

  • Green chemical and hybrid enzymatic pretreatments for lignocellulosic biorefineries: Mechanism and challenges

    Publikacja

    The greener chemical and enzymatic pretreatments for lignocellulosic biomasses are portraying a crucial role owing to their recalcitrant nature. Traditional pretreatments lead to partial degradation of lignin and hemicellulose moieties from the pretreated biomass. But it still restricts the enzyme accessibility for the digestibility towards the celluloses and the interaction of lignin-enzymes, nonproductively. Moreover, incursion...

  • Trust-Based Model for the Assessment of the Uncertainty of Measurements in Hybrid IoT Networks

    Publikacja

    - SENSORS - Rok 2020

    The aim of this paper is to introduce a NUT model (NUT: network-uncertainty-trust) that aids the decrease of the uncertainty of measurements in autonomous hybrid Internet of Things sensor networks. The problem of uncertainty in such networks is a consequence of various operating conditions and varied quality of measurement nodes, making statistical approach less successful. This paper presents a model for decreasing the uncertainty...

    Pełny tekst do pobrania w portalu

  • Hybrid Expert System for Computer-Aided Design of Ship Thruster Subsystems

    Publikacja

    The article presents an expert system supporting the design of ship's power subsystems, in particular the thruster subsystem. The proposed hybrid expert system uses the results of simulation tests as the additional source of knowledge. The results of system operation are collated in a report which can be used as part of ship design description. The work oriented on developing the expert system is the continuation of the research...

    Pełny tekst do pobrania w portalu

  • Hybrid technique for the analysis of circular waveguide junctions loaded with ferrite posts

    This study presents a hybrid technique for the analysis of circular waveguide junctions loaded with axially symmetrical ferrite posts of irregular shape. The method is based on a combination of the finite-difference frequency- domain technique with a mode-matching technique. The proposed approach is validated by comparing the presented results with numerical ones obtained from commercial software. The application of a cylindrical...

    Pełny tekst do pobrania w portalu

  • Resonance Frequency Calculation of Spherical Microstrip Structure Using Hybrid Technique

    In this paper the spherical microstrip structure is considered. The structure is composed of a metallic patch with an arbitrary shape placed on a dielectric coated metallic sphere. In the analysis the hybrid technique is utilized. In this approach the finite-difference technique is applied in a cavity model to determine the current basis functions on the patch. Next, using method of moments, the resonance frequency of the structure...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Comparison of Properties of the Hybrid and Bilayer MWCNTs—Hydroxyapatite Coatings on Ti Alloy

    Publikacja

    - Coatings - Rok 2019

    Carbon nanotubes are proposed for reinforcement of the hydroxyapatite coatings to improve their adhesion, resistance to mechanical loads, biocompatibility, bioactivity, corrosion resistance, and antibacterial protection. So far, research has shown that all these properties are highly susceptible to the composition and microstructure of coatings. The present research is aimed at studies of multi-wall carbon nanotubes in three different...

    Pełny tekst do pobrania w portalu

  • Calculation of Resonance in Planar and Cylindrical Microstrip Structures Using a Hybrid Technique

    A hybrid technique was employed for the analysis of the resonance frequency of thin planar and cylindrical microstrip structures with the patches of arbitrary geometry. The proposed technique utilizes a combination of Galerkin’s moment method and a finite-element method (FEM). In this approach, an FEM is adopted to calculate the patch surface current densities, and a method of moments is utilized to calculate the resonance frequencies...

    Pełny tekst do pobrania w portalu

  • Hybrid Technique for the EM Scattering Analysis with the Use of Ring Domain Decomposition

    A hybrid technique combining finite-element and mode-matching methods for the analysis of scattering problems in open space is presented here. The main idea is based on impedance matrix descriptions of the boundary surrounding the discrete computational domain and combine it with external field described analytically. The discrete analysis, which is the most time- and memory-consuming, is limited here only to the close proximity...

  • Hybrid evolutionary partitioning algorithm for heat transfer enhancement in VLSI circuits

    W niniejszym artykule przedstawiono metodę pozwalającą na polepszenie transferu ciepła z układu scalonego do otoczenia poprzez zwiększenie liczby połączeń zewnętrznych, co pozwoliło na polepszenie przewodności cieplnej układu scalonego. Dla osiągnięcia tego celu opracowano nowy, hybrydowy, ewolucyjny algorytm podziału (ang. Hybrid Evolutionary Partitioning Algorithm - HEPA). Obliczenia przeprowadzone dla wybranych przykładów testowych...

  • Krzysztof Jan Kaliński prof. dr hab. inż.

    Ukończył studia magisterskie na Wydziale Mechanicznym Technologicznym (MT) PG (1980, dyplom z wyróżnieniem). Stopień doktora otrzymał na Wydziale Budowy Maszyn PG (1988, praca wyróżniona), stopień doktora habilitowanego na Wydziale Mechanicznym (WM) PG (2002, praca wyróżniona), a tytuł profesora nauk technicznych – w 2013 r. Od 2015 r. jest profesorem zwyczajnym, a od 2019 r. - profesorem. Obszar jego badań naukowych obejmuje:...

  • Electrical properties of organic and perovskite systems used in solar cells

    Publikacja

    - Rok 2019

    Nowadays, a great progress in the areas of molecular and hybrid photovoltaics is observed. The devices based on organic and perovskite materials are getting attention mostly due to their low cost production process. However, their efficiency and stability are still lower than for inorganic materials which make them less popular. Therefore, a detailed understanding of the device physics is fundamental for organic and perovskite...

    Pełny tekst do pobrania w portalu

  • Novel structure and design of enhanced-bandwidth hybrid quadrature patch coupler

    A novel structure and design optimization procedure of an enhanced-bandwidth hybrid quadrature patch coupler is proposed. Improved performance of the circuit has been obtained by parameterizing the coupler sections using splines, which introduces additional degrees of freedom. Due to computational complexity of the parameter adjustment problem, a sequential design procedure is applied. In each iteration, a selected number of spline...

    Pełny tekst do pobrania w portalu

  • Building Project and Project Team Characteristics For Creating Hybrid Management Processes

    Publikacja
    • C. Orłowski
    • T. Deręgowski
    • M. Kurzawski
    • A. Ziółkowski
    • B. Chrabski

    - Rok 2016

    This paper introduces a method of building the characteristic of Software Development Project. Project characteristic is determined on the basis of several factors such as the complexity of Software Development Project and Project Team, results of historical projects and information on processes and methodologies, which are implemented in analyzed organizations. Information on project complexity can be applied to many different...

  • Real-time hybrid model of a wind turbine with doubly fed induction generator

    Publikacja

    - Rok 2019

    In recent years renewable sources have been dominating power system. The share of wind power in energy production increases year by year, which meets the need to protect the environment. Possibility of conducting, not only computer simulation, but also laboratory studies of wind turbine operation and impact on the power system and other power devices in laboratory conditions would be very useful. This article presents a method...

    Pełny tekst do pobrania w portalu

  • OPTIMIZATION OF THE LAST STAGE OF GAS-STEAM TURBINE USING A HYBRID METHOD

    Publikacja

    - Rok 2021

    This paper relates to the CFD calculation of a new turbine type which is in the phase of theoretical analysis, because the working fluid is a mixture of steam and gas generated in wet combustion chamber. At first, this article concentrates on a possibility of streamlining the flow efficiency of a last stage of axial turbine working on gas-steam mixture using a hybrid of the particle swarm optimization algorithm with the Nelder-Mead...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Hybrid DUMBRA: an efficient QoS routing algorithm for networks with DiffServ architecture

    Publikacja

    - Rok 2011

    Dynamic routing is very important issue of current packet networks. It may support the QoS and help utilize available network resources. Unfortunately current routing mechanisms are not sufficient to fully support QoS. Although many research has been done in this area no generic QoS routing algorithm has been proposed that could be used across all network structures. Existing QoS routing algorithms are either dedicated to limited...

  • AC-DC-DC Converter for Small Power Energy Storage Systems

    Publikacja

    - ENERGIES - Rok 2023

    The energy transformation driven by the development of renewable energy sources has become a reality for all power grid users. Prosumer energy, primarily utilizing photovoltaic installations, is one of the fastest-growing market segments. The advancement of technology, a decrease in electrochemical energy storage prices, and changes in the legal framework governing energy billing for grid-fed power have led to a growing interest...

    Pełny tekst do pobrania w portalu

  • Justyna Signerska-Rynkowska dr inż.

    Since 2021 visiting assistant professor in Dioscuri Centre in Topological Data Analysis (Institute of Mathematics of the Polish Academy of Sciences, IMPAN)  Since 2016   assistant professor at Gdańsk University of Technology, Faculty of Applied Physics and                      Mathematics, Department of Differential Equations and Mathematics Applications  2020 - 2023  Principal Investigator in "SONATA" grant “Challenges of low-dimensional...

  • Using terrestrial laser scanning in inventorying of a hybrid constructed wetland system

    Publikacja
    • R. Obroślak
    • A. Mazur
    • K. Jóźwiakowski
    • O. Dorozhynskyy
    • A. Grzywna
    • R. Rybicki
    • K. Nieścioruk
    • Ż. Król
    • J. Gabryszuk
    • M. Gajewska

    - WATER SCIENCE AND TECHNOLOGY - Rok 2017

    The goal of this paper was to evaluate the possibility of using terrestrial laser scanning (TLS) for inventorying of a hybrid constructed wetland (CW) wastewater treatment plant. The object under study was a turtle-shaped system built in 2015 in Eastern Poland. Its main purpose is the treatment of wastewater from theMuseumand Education Centre of Polesie National Park. The study showed that the CW system had been built in compliance...

    Pełny tekst do pobrania w portalu

  • Reliable routing and resource allocation scheme for hybrid RF/FSO networks

    Publikacja

    - Rok 2014

    Significant success of wireless networks in the last decade has changed the paradigms of communication networks design. In particular, the growing interest in wireless mesh networks (WMNs) is observed. WMNs offer an attractive alternative to conventional cable infrastructures, especially in urban areas, where the cost of new installations is almost prohibitive. Unfortunately, the performance of WMNs is often limited by the cluttered...

    Pełny tekst do pobrania w serwisie zewnętrznym

  • Four Degree-of-Freedom Hydrodynamic Maneuvering Model of a Small Azipod-Actuated Ship With Application to Onboard Decision Support Systems

    Publikacja

    - IEEE Access - Rok 2023

    The main contribution of this paper is a numerical ship motion model of NTNU’s research vessel Gunnerus, capturing the surge, sway, roll, and yaw dynamics when sailing in uniform and steady currents. The model utilizes a crossflow drag formulation for the transverse viscous loads, and it includes a nonlinear formulation for the propulsion and steering loads provided by two azipod thrusters. A wide range of experimental data obtained...

    Pełny tekst do pobrania w portalu

  • Analysis of volatile fraction selected hybrid fruits using chromatographic techniques

    At present, "healthy eating" is gaining in popularity. Many people associate this term with eating plenty of vegetables and fruits. The basic elements influencing the selection of fruit are their appearance and smell. Of course, their origin and impact on human health are also very important. In recent years, exotic fruits have become increasingly accessible, making them gaining popularity, even among Poles. You can also meet plants...

    Pełny tekst do pobrania w portalu

  • Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems

    Publikacja

    This paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order...

    Pełny tekst do pobrania w portalu