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Recent items
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Heave Plates with Holes for Floating Offshore Wind Turbines
- Ewelina Ciba
- Paweł Dymarski
- Mirosław Grygorowicz
The paper presents an innovative solution which is heave plates with holes. The long-known heave plates are designed to damp the heave motion of platforms. They are most often used for Spar platforms. The growing interest in this type of platform as supporting structures for offshore wind turbines makes it necessary to look for new solutions. Based on the available literature and the authors’ own research, it was concluded that the main element responsible for the damping of heave plates is not so much the surface of the plate, but its edge. Therefore, it was decided to investigate the effect of the holes in heave plates on their damping coefficient. Model tests and CFD calculations were performed for three different structures: a smooth cylinder, a cylinder with heave plates with a diameter of 1.4 times the diameter of the cylinder, and a cylinder with the same plate, in which 24 holes were cut (Fig. 1). Free Decay Tests (FDT) were used to determine the damping coefficient and the natural period of heave, and then the values obtained were compared. The full and punched heave-plate designs were also tested with regular waves of different periods to obtain amplitude characteristics. The results obtained are not unequivocal, as a complex motion appears here; however, it is possible to clearly define the area in which the damping of a plate with holes is greater than that of a full plate.
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Hebb–Wagner polarization method for determining the oxygen ion conductivity in barium cerate-zirconate
- Tadeusz Miruszewski
- Kacper Dzierzgowski
- Piotr Winiarz
- Sebastian Wachowski
- Aleksandra Mielewczyk-Gryń
- Maria Gazda
In this work, the partial conductivity of oxygen ions in BaCe0.6Zr0.2Y0.2O3 was studied at different temperatures and water partial pressures. For this purpose, a modified DC Hebb–Wagner polarization method with an electrode blocking for protons and electrons was used. A new type of measuring cell as well as a suitable calculation model were proposed for the determination of partial oxygen ionic conductivity in materials with three mobile charge carriers, namely, oxygen ions, protons and electrons. The obtained oxygen ion partial conductivity (σO) in the BaCe0.6Zr0.2Y0.2O3 mixed protonic oxygen ionic–electronic conductor was 2.3 × 10−3 S cm−1 at 800 °C and pO2 = 0.20 atm, pH2O = 0.023 atm. This is in agreement with the literature reports and indicates the feasibility of this method for characterization of mixed-conducting ceramics with unknown oxygen ionic conductivity. The obtained results also indicate the influence of protons on the conduction mechanism of oxygen ions. This information may be very useful for the analysis of the interaction between the charge carriers in mixed conducting materials.
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High Dynamic Range Microwave Displacement and Rotation Sensors Based on the Phase of Transmission in Groove Gap Waveguide Technology
- Ali Karami Horestani
- Zahra Shaterian
- Michał Mrozowski
This research is focused on the design and realization of displacement sensors in gap waveguide technology. It is shown that with a small but fundamental change in the structure of a conventional gap waveguide, a linear displacement can be sensed. To this end, a unique feature of gap waveguides, i.e. the fact that no electrical connection between the top and bottom parts of the gap waveguide is required, is used. It is further shown that the concept can be also used for the development of rotation sensors. To validate the proposed concept linear and angular displacement sensors are designed and simulated. A prototype of the proposed linear displacement sensor is fabricated for demonstration. Agreement between the computed and measured results validates the concept.
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High gain/bandwidth off‑chip antenna loaded with metamaterial unit‑cell impedance matching circuit for sub‑terahertz near‑field electronic systems
- Mohammad Alibakhshikenari
- Bal S. Virdee
- Dion Mariyanayagam
- Valeria Vadala
- Mohammad Naser-moghadasi
- Chan Hwang See
- Iyad Dayoub
- Sonia Aissa
- Patrizia Livreri
- Shah Nawaz Burokur
- Anna Pietrenko-Dąbrowska
- Francisco Falcone
- Sławomir Kozieł
- Ernesto Limiti
An innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance bandwidth is enhanced by a factor of two and its gain on average by about 4 dB. Unlike conventional antennas, where the energy is dissipated in a resistive load, the technique proposed here significantly reduces losses. The antenna is excited from underneath the antenna by coupling RF energy from an open-circuited feedline through a slot in the ground-plane of the middle substrate layer. The feedline is shielded with another substrate layer which has a ground-plane on its opposite surface to mitigate the influence of the structure on which the antenna is mounted. The antenna has the dimensions 12.3 × 4.5 × 0.905 mm3 and operates across the 0.137–0.158 THz band corresponding to a fractional bandwidth of 14.23%. Over this frequency range the average measured gain and efficiency are 8.6 dBi and 77%, respectively. These characteristics makes the proposed antenna suitable for integration in sub-terahertz near-field electronic systems such as radio frequency identification (RFID) devices with high spatial resolution.
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High-conducting Bi4V2-xFexO11-δ ceramics containing Fe2O3 nanocrystals: Structure and properties
- Natalia Wójcik
- Katarzyna Polcyn
- Jakub Karczewski
- Karolina Górnicka
- Ryszard Barczyński
The topography, structure, thermal, magnetic, and electrical properties of Bi4V2-xFexO11-δ ceramics substituted with x = 0.5 and 0.7 Fe were studied. The microscope analysis showed the presence of iron-rich nanocrystals formed on the Bi-Fe-V-O grains. The X-ray diffraction studies confirmed that grains are built mostly of tetragonal Bi4V1.5Fe0.5O10.5 phase. Thermal properties analysis showed an order-disorder type γ ↔ γʹ phase transition at a temperature of around 916 K, pronounced in samples doped with x = 0.5 Fe. The magnetic anomaly was observed in ceramics doped with x = 0.7 Fe which was assigned to Morin transition of Fe2O3. The conductivity was measured over a wide frequency range from 10 mHz to 1 MHz and at a wide temperature range from 373 to 923 K, using impedance spectroscopy. The D.C. conduction process was due to oxygen vacancies hopping while at low temperatures electron holes hopping is also possible.
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High-density Polyethylene - Expanded Perlite Composites: Structural Oriented Analysis of Mechanical and Thermomechanical Properties
- Mateusz Barczewski
- Aleksander Hejna
- Paulina Kosmela
- Olga Mysiukiewicz
- Adam Piasecki
- Kamila Sałasińska
As part of this work, research was carried out on the effect of the addition of expanded perlite (PR) on the mechanical and thermomechanical properties of high-density polyethylene (PE) composites. Composites containing from 1 to 10 wt% of the inorganic filler were produced. Polyethylene-based composites manufactured by twin-screw extrusion and formed in the compression molding process were subjected to mechanical, thermomechanical, and structural analyses. The structure of polymer composites and filler was analyzed using scanning electron microscopy (SEM). It has been correlated with the static tensile tests and results of dynamic thermomechanical analysis (DMA). As part of the work, several thermomechanical parameters were calculated, and the obtained results were discussed with the evaluation of interfacial adhesion based on microscopic analysis. The research indicate that despite introducing a 10 wt% of particle-shaped filler, the composites show increased stiffness without noticeable deterioration in tensile strength, simultaneously reducing toughness and brittleness. The analysis of the thermomechanical properties showed the lack of significant effects of the filler influence on the polymer matrix.
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High-density polyethylene/EPDM rubber blend composites of boron compounds for neutron shielding application
- Sajith Thottathil Abdulrahman
- Bindu Patanair
- Vineeth Puthuparampil Vasukuttan
- Sabu Thomas
- Emmanuel Cadel
- Fabien Cuvilly
- Allisson Saiter-Fourcin
- Zakiah Ahmad
- Maciej Jaroszewski
- Michal Strankowski
- David Laroze
Novel materials with neutron shielding property were fabricated by incorporating boron compounds into highdensity polyethylene (HDPE)/Ethylene propylene diene monomer rubber (EPDM) blends. A detailed investigation on the morphological, thermal, mechanical, and neutron attenuation properties of suitable proportion of HDPE/EPDM blend with boric acid (BA), boron carbide (BC), and nano boron carbide (NBC) were performed. Morphology of the 20 wt% of EPDM shows better distribution in HDPE matrix. BA filler is localised in the HDPE phase, while NBC shows uniform distribution in HDPE/EPDM blend compared to its micro counterpart.
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Higher platelet counts correlate to tumour progression and can be induced by intratumoural stroma in non-metastatic breast carcinomas
- Natalia Bednarz-Knoll
- Marta Popęda
- Tomasz Kryczka
- Barbara Kozakiewicz
- Katarzyna Pogoda
- Jolanta Szade
- Aleksandra Markiewicz
- Damian Strzemecki
- Leszek Kalinowski
- Jarosław Skokowski
- Jian Liu
- Anna Żaczek
Background Platelets support tumour progression. However, their prognostic significance and relation to circulating tumour cells (CTCs) in operable breast cancer (BrCa) are still scarcely known and, thus, merit further investigation. Methods Preoperative platelet counts (PCs) were compared with clinical data, CTCs, 65 serum cytokines and 770 immune-related transcripts obtained using the NanoString technology. Results High normal PC (hPC; defined by the 75th centile cut-off) correlated with an increased number of lymph node metastases and mesenchymal CTCs in the 70 operable BrCa patients. Patients with hPC and CTC presence revealed the shortest overall survival compared to those with no CTC/any PC or even CTC/normal PC. Adverse prognostic impact of hPC was observed only in the luminal subtype, when 247 BrCa patients were analysed. hPC correlated with high content of intratumoural stroma, specifically its phenotype related to CD8+ T and resting mast cells, and an increased concentration of cytokines related to platelet activation or even production in bone marrow (i.e. APRIL, ENA78/CXCL5, HGF, IL16, IL17a, MDC/CCL22, MCP3, MMP1 and SCF). Conclusions Preoperative platelets evaluated alone and in combination with CTCs have prognostic potential in non-metastatic BrCa and define patients at the highest risk of disease progression, putatively benefiting from anti-platelet therapy.
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Highly antifouling polymer-nanoparticle-nanoparticle/polymer hybrid membranes
- Vahid Vatanpour
- Maryam Jouyandeh
- Seyed Soroush Mousavi Khadem
- Shadi Paziresh
- Ahmad Dehghan
- Mohammad Ganjali
- Hiresh Moradi
- Somayeh Mirsadeghi
- Alireza Badiei
- Muhammad Tajammal Munir
- Ahmad Mohaddespour
- Navid Rabiee
- Sajjad Habibzadeh
- Amin Hamed Mashhadzadeh
- Sasan Nouranian
- Krzysztof Formela
- Mohammad Saeb
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 nanocomposites were determined using Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Moreover, microstructure and physicochemical properties of HNT-SiO2-PEI/PVC membranes were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), and attenuated total reflectance (ATR)-FTIR. Results of these analyses indicated that the overall porosity and mean pore size of nanocomposite membranes were enhanced, but the surface roughness was reduced. Additionally, surface hydrophilicity and flexibility of the original PVC membranes were significantly improved by incorporating HNT-SiO2-PEI nanoparticles. Based on pure water permeability and bovine serum albumin (BSA)/dye rejection tests, the highest nanoparticle-embedded membrane performance was observed at 2 weight percent (wt%) of HNT-SiO2-PEI. The nanocomposite incorporation in the PVC membranes further improved its antifouling performance and flux recovery ratio (96.8%). Notably, dye separation performance increased up to 99.97%. Overall, hydrophobic PVC membranes were successfully modified by incorporating HNT-SiO2-PEI nanomaterial and better-quality wastewater treatment performance was obtained.
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Highly efficient maximum power point tracking control technique for PV system under dynamic operating conditions
- Syed Kumayl Raza Moosavi
- Majad Mansoor
- Muhammad Hamza Zafar
- Noman Mujeeb Khan
- Adeel Mirza
- Naureen Akhtar
The application of small-scale electrical systems is widespread and the integration of Maximum Power Point Tracking (MPPT) control for Photovoltaic systems with battery applications further enhances the techno-economic feasibility of renewable systems. For this purpose, a novel MPPT control system using Dynamic Group based cooperation optimization (DGBCO) algorithm is utilized for PV systems. The population in the DGBCO is divided into exploration and exploitation groups. Due to effective mathematical modeling, the drawbacks of existing MPPT control techniques are undertaken. The drawbacks of modern MPPT control become prominent under partial shading conditions (PSC) which give rise to power loss, random fluctuations, and slow control action. The DGBCO is implemented using a search and skip mechanism which significantly enhances the performance of the MPPT controller and improves the efficiency of PV systems. The results are compared with recently developed Artificial Bee Colony (ABC), Cuckoo Search Algorithm (CS), DragonFly Optimizer (DFO), and Particle Swarm Optimization (PSO) techniques. The operating conditions case studies include fast varying irradiance and PS with skewed GM. The DGBCO based MPPT control technique is also validated by the experimental setup. The results are compared using statistical and analytical indices such as tracking time, settling time, power tracking efficiency, total energy, RMSE, MAE, and RE. The results show the superior performance of the proposed DGBCO. Relatively, 2%–8% higher energy harvest, and up to 60% faster tracking time helps to achieve up to 99.86% power tracking efficiency in both transient and steady-state control operation. Lower values of statistical metrices i.e. RMSE, MAE, and SR indicate the robustness and effective mathematic modeling of DGBCO for effective MPPT of PV systems under PS conditions.
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Highly Reliable Passive RFID-Based Inductor–Capacitor Sensory System Strengthened by Solvatochromism for Fast and Wide-Range Lactate Detection
- Md. Rajibur Rahaman Khan
- Alireza Khalilian
- Jungyoon Seo
- Seungtaek Oh
- Atul Thakre
- Tae Kyu An
- Hwa Sung Lee
A passive radio frequency-identification-based inductor-capacitor (LC) lactate sensory system with a specific dye-containing interdigitated capacitor (IDC) in which the sensing signal is amplified by the solvatochromic effect is proposed. When a lactate solution contacts the IDC of the LC lactate sensor, the capacitance of the IDC changes, changing the resonance frequency of the sensor. This changes the oscillation frequency of the Colpitts oscillator in the readout circuit. By analyzing the frequency changes, the concentration of the lactate solution can be measured quickly and accurately over a wide range. To our knowledge, the proposed device is the first passive, battery-free LC lactate sensor that uses solvatochromic dye-containing IDC sensing elements to detect lactate solution concentrations. Four solvatochromic dyes were tested and incorporated into a polymer as the lactate-sensitive membranes of the IDCs. The proposed LC sensor tag offers excellent sensitivity and linearity over a wide lactate concentration range of about 10μM to 1 M. The response and recovery times of our LC sensory system were significantly shorter than those of previously reported lactate sensors. Our results are useful for the development of reliable wearable devices capable of real-time lactate detection at a low cost.
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Highly sensitive large strain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite foams: From design to performance evaluation
- Yanpei Fei
- Ruitao Jiang
- Wei Fang
- Tong Liu
- Mohammad Saeb
- Aleksander Hejna
- Morteza Ehsani
- Mateusz Barczewski
- S. Mohammad Sajadi
- Feng Chen
- Tairong Kuang
Aerogel-based polymer composite foams are promising for large strain piezoresistive sensors, but their aerogel skeleton is partially destroyed during the foaming process, limiting their sensitivity. Herein, the thermoplastic polyurethane was synthesized on the aerogel skeleton to obtain cellulose/multiwalled carbon nanotubes (MWCNTs)/thermoplastic polyurethane (TPU) nanocomposite materials foamed with the aid of supercritical carbon dioxide (ScCO2). A series of lightweight, high strength, and high sensitivity nanocomposite foams were developed, possessing an average diameter of ~9.11 μm and a cell density of 6.84×108 cells/cm3. The mechanical properties, including compressive strength and compressive modulus, were promisingly 5.56 and 28.90 MPa, respectively. Under 50% strain, apparent high repeatability of force-to-electricity conversion behavior was detected in 100 compression cycles.
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Highly-Miniaturized Dual-Mode Bandpass Filter Based on Quarter-Mode Substrate Integrated Waveguide with Wide Stopband
- Rusan Kumar Barik
- Sławomir Kozieł
- Stanisław Szczepański
This paper presents a novel design of a highly-miniaturized dual-mode bandpass filter (BPF) employing a quarter-mode substrate integrated waveguide (QMSIW). The QMSIW resonator is based on a square cavity with metallic vias along two sides, and open-ended edges at the remaining sides that contain orthogonal feed lines. An open slot is introduced along the two sides of the square cavity with metallic vias to form a magnetic wall. A single metallic via is assigned at the corner of the two open-edged sides to form an electrical wall, which produces different resonances. By loading a slot diagonally, the mode frequencies can be controlled independently, which allows us to realize a second-order BPF. The detailed design steps and a flowchart explaining the filter’s topology evolution are presented. The eigen-mode analysis, field distributions, coupling matrix, and full-wave simulation of the proposed QMSIW filter topology are used to determine the filter’s operating principle. To verify the proposed theory, a second-order BPF is realized, fabricated, and demonstrated experimentally. The BPF prototype exhibits excellent performance such as a small footprint of 0.019λ2, a wide passband of 34.8-percent, low insertion loss of 0.43 dB, and a wide stopband of 3.36f0 with a rejection level greater than 20 dB. Excellent consistency is found between the EM-simulated and measured responses of the device.
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High-performance anode-supported solid oxide fuel cells with co-fired Sm0.2Ce0.8O2-δ/La0.8Sr0.2Ga0.8Mg0.2O3−δ/Sm0.2Ce0.8O2-δ sandwiched electrolyte
- Sea-Fue Wang
- Hsi-Chuan Lu
- Yung-Fu Hsu
- Piotr Jasiński
In this study, intermediate-temperature solid oxide fuel cells (IT-SOFCs) with a nine-layer structure are constructed via a simple method based on the cost-effective tape casting-screen printing-co-firing process with the structure composed of a NiO-based four-layer anode, a Sm0.2Ce0·8O2-δ(SDC)/La0·8Sr0.2Ga0.8Mg0·2O3−δ (LSGM)/SDC tri-layer electrolyte, and an La0·6Sr0·4Co0·2Fe0·8O3-δ (LSCF)-based bi-layer cathode. The resultant SDC (4.14 μm)/LSGM (1.47 μm)/SDC (4.14 μm) tri-layer electrolyte exhibits good continuity and a highly dense structure. The Ro and Rp values of the single cell are observed to be 0.15 and 0.08 Ω cm2 at 800 °C, respectively, and the MPD of the cell is 1.08 Wcm-2. The high MPD of the cell appears to be associate with the significantly lower area-specific resistance and the reasonably high OCV. Compared to those with a similar electrolyte thickness reported in prior studies, the nine-layer anode-supported IT-SOFC with a tri-layer electrolyte developed by the study demonstrates superior cell properties.
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High-performance graphene-based biosensor using a metasurface of asymmetric silicon disks
- Mohammad Salemizadeh Parizi
- Fatemeh Salemizadehparizi
- Mahdi Molaei Zarasvand
- Saeed Abdolhosseini
- Shahram Bahadori-Haghighi
- Alireza Khalilian
In recent years, optical biosensors widely applicable for medical applications, have received much attention. In this paper, we propose a high-performance polarization-insensitive optical biosensor based on a graphene-dielectric metasurface. The metasurface consists of an asymmetric dielectric disk array that supports a high Q-factor Fano resonance. The provided sharp Fano resonance results in an enhanced light-matter interaction leading to a highly sensitive biosensor. The proposed structure is analyzed using the finite element method and the corresponding transmission and reflection spectra are calculated. According to the presented results, a sensitivity of as high as 550 nm/RIU, linearity R2 value of 0.999 with a figure of merit (FOM) more than 378 RIU-1 around the operating wavelength of 1550 nm are obtained. This is the largest FOM ever reported for a polarization-insensitive biosensor. Such a large FOM accompanied by high sensitivity and linearity make our proposed graphene-based biosensor promising for the effective detection of biomolecules like hemoglobin.
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High-resolution fire danger forecast for Poland based on the Weather Research and Forecasting Model
- Alan Mandal
- Grzegorz Nykiel
- Tomasz Strzyzewski
- Adam Kochanski
- Weronika Wrońska
- Marta Gruszczynska
- Mariusz Figurski
Due to climate change and associated longer and more frequent droughts, the risk of forest fires increases. To address this, the Institute of Meteorology and Water Management implemented a system for forecasting fire weather in Poland. The Fire Weather Index (FWI) system, developed in Canada, has been adapted to work with meteorological fields derived from the high-resolution (2.5 km) Weather Research and Forecasting (WRF) model. Forecasts are made with 24- and 48-h lead times. The purpose of this work is to present the validation of the implemented system. First, the results of the WRF model were validated using in situ observations from ~70 synoptic stations. Second, we used the correlation method and Eastaugh’s percentile analysis to assess the quality of the FWI index. The data covered the 2019 fire season and were analysed for the whole forest area in Poland. Based on the presented results, it can be concluded that the FWI index (calculated based on the WRF model) has a very high predictive ability of fire risk. However, the results vary by region, distance from human habitats, and size of fire.
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High-Speed Binary-to-Residue Converter Design Using 2-Bit Segmentation of the Input Word
- Robert Smyk
- Maciej Czyżak
In this paper a new approach to the design of the high-speed binary-to-residue converter is proposed that allows the attaining of high pipelining rates by eliminating memories used in modulo m generators. The converter algorithm uses segmentation of the input binary word into 2-bit segments. The use and effects of the input word segmentation for the synthesis of converters for five-bit moduli are presented. For the number represented by each segment, the modulo m reduction using a segment modulo m generator is performed. The use of 2-bit segments substantially reduces the hardware amount of the layer of input modulo m generators. The generated residues are added using the multi-operand modulo m adder based on the carry-save adder (CSA) tree, reduction of the number represented by the output CSA tree vectors to the 2m range and fast two-operand modulo m additions. Hardware amount and time delay analyses are also included.
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High-temperature Co-electrolysis of CO2/H2O and direct methanation over Co-impregnated SOEC. Bimetallic synergy between Co and Ni
- Patryk Błaszczak
- Marcin Zając
- Agata Ducka
- Krzysztof Matlak
- Barbara Wolanin
- Sea-Fue Wang
- Anna Mandziak
- Beata Bochentyn
- Piotr Jasiński
To study the synergy between the transition metals for enhancing the electrochemical and chemical activity, a series of SOECs were modified with a small amount of Co ions, namely 1.8, 3.6, and 5.4 wt% in the reduced state. The addition of βCD into the precursor solution allowed for extremely fine dispersion of Co species across the Ni-YSZ cermet structure. The sample containing 3.6 wt% Co reached an outstanding over 2.5-times-higher concentration of CH4 in the outlet stream. At the same time, the Co greatly enhanced the electrochemical efficiency of water and CO2 co-electrolysis. Full characterization involving STXM imaging allowed for better understanding of the synergy between the Ni and Co host metal and made it possible to find the causes of the increased activity. It revealed the complexity of the substructures formed within the electrode. A novel discovery was described regarding the NiCo2O4 spinel structure subjected to the O2-TPO measurements. Despite the applied oxidizing atmosphere, the catalyst evolved oxygen at elevated temperatures in a reversible manner. The performance tests indicated the roles of both rWGS and direct electrolysis of CO2 in the electroreduction process. The addition of Co did not influence the prolonged degradation of the cell.
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Hommage a Profesor Kazimierz Ostrowski. Pamięć obrazów.
- Jan Buczkowski
Impulsem do stworzenia wystawy, było przekazanie Uczelni przez córkę Profesora Kazimierza Ostrowskiego, Panią Honoratę Pilszyk, podobrazi, jakie pozostawił po sobie Mistrz. Były to płótna zagruntowane przez Artystę osobiście, gotowe do dalszej pracy, niektóre z ledwo zaczętym szkicem lub próbą pozostawionego koloru. Gdy zobaczyłem je w pracowni w Gdyni (a było to w 2015 roku), pomyślałem, że te podkłady mogłyby stać się inspiracją do stworzenia nowych prac, rodzaju symbolicznej kontynuacji, dokończenia dzieła przez innych malarzy. Przygotowanie wystawy prac namalowanych przez innych twórców, na płótnach należących do Kazimierza Ostrowskiego, było ideą intrygującą, wartą zaangażowania. Podobrazia dość szybko powędrowały nie tylko do jego absolwentów i przyjaciół, ale także artystów z innych ośrodków, przyjaciół związanych z Galerią Koło (w której prace Profesora prezentowane były na wystawie inaugurującej działalność galerii w 1995 roku). Gest ten został przyjęty z zainteresowaniem jako duże wyzwanie artystyczne. Ponieważ ilość podarowanych „Kachowych” płócien była ograniczona, wracając ponownie do pomysłu realizacji wystawy, postanowiłem ją rozszerzyć. Zaproponowałem udział w wystawie wszystkim pracownikom Wydziału Malarstwa Akademii Sztuk Pięknych w Gdańsku. Celem wystawy jest wyrażenie uznania dla twórczej postawy Kazimierza Ostrowskiego i jego artystycznych zmagań. Jest to także wyzwanie wobec historii i dziedzictwa kultury. Warto przekazywać naszą wspólną historię nowym pokoleniom, które stają się jej symbolicznymi spadkobiercami. Poprzez udział artystów różnych generacji, będziemy mogli przyjrzeć się artystycznym ideom, które mimo pokoleniowych różnic, posiadają wspólny rodowód. Istotny jest także modernistyczny rys w twórczości Profesora i jej relacja z malarstwem współczesnym. Ważną częścią projektu jest wydawnictwo, które zostanie zrealizowane po wystawie. Biorący udział w tym przedsięwzięciu artyści, będą mogli zaprezentować nie tylko swoje dzieła, ale także wspomnienia związane z Profesorem oraz refleksje odnoszące się do czasów studiów na Wydziale Malarstwa. To niecodzienne spotkanie jest dla nas wszystkich okazją, by oddać hołd Profesorowi oraz docenić Jego wiarę w sztukę i przepełnione pasją oddanie profesji malarza.
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Hommage à Profesor Kazimierz Ostrowski. Pamięć obrazów
- Krzysztof Wróblewski
Impulsem do stworzenia wystawy, było przekazanie Uczelni przez córkę Profesora Kazimierza Ostrowskiego, Panią Honoratę Pilszyk, podobrazi, jakie pozostawił po sobie Mistrz. Były to płótna zagruntowane przez Artystę osobiście, gotowe do dalszej pracy, niektóre z ledwo zaczętym szkicem lub próbą pozostawionego koloru.(...) Przygotowanie wystawy prac namalowanych przez innych twórców, na płótnach należących do Kazimierza Ostrowskiego, było ideą intrygującą, wartą zaangażowania. Podobrazia dość szybko powędrowały nie tylko do jego absolwentów i przyjaciół, ale także artystów z innych ośrodków, przyjaciół związanych z Galerią Koło (w której prace Profesora prezentowane były na wystawie inaugurującej działalność galerii w 1995 roku).(...) Ponieważ ilość podarowanych „Kachowych” płócien była ograniczona, wracając ponownie do pomysłu realizacji wystawy, postanowiłem ją rozszerzyć. Zaproponowałem udział w wystawie wszystkim pracownikom Wydziału Malarstwa Akademii Sztuk Pięknych w Gdańsku. Ważny jest udział w projekcie najmłodszych pracowników Wydziału Malarstwa, którzy nie mieli okazji poznania profesora Kazimierza Ostrowskiego, znają osobę Profesora tylko z opowieści. Celem wystawy jest wyrażenie uznania dla twórczej postawy Kazimierza Ostrowskiego i jego artystycznych zmagań. Jest to także wyzwanie wobec historii i dziedzictwa kultury. (...) Poprzez udział artystów różnych generacji, będziemy mogli przyjrzeć się artystycznym ideom, które mimo pokoleniowych różnic, posiadają wspólny rodowód. Istotny jest także modernistyczny rys w twórczości Profesora i jej relacja z malarstwem współczesnym. (...) Ważną częścią projektu jest wydawnictwo, które zostanie zrealizowane po wystawie. Biorący udział w tym przedsięwzięciu artyści, będą mogli zaprezentować nie tylko swoje dzieła, ale także wspomnienia związane z Profesorem oraz refleksje odnoszące się do czasów studiów na Wydziale Malarstwa. To niecodzienne spotkanie jest dla nas wszystkich okazją, by oddać hołd Profesorowi oraz docenić Jego wiarę w sztukę i przepełnione pasją oddanie profesji malarza. Krzysztof Gliszczyński - kurator wystawy
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Hopping or Tunneling? Tailoring the Electron Transport Mechanisms through Hydrogen Bonding Geometry in the Boron-Doped Diamond Molecular Junctions
- Adrian Olejnik
- Bartłomiej Dec
- William A. Goddard III
- Robert Bogdanowicz
Mechanisms of charge transport in molecular junctions involving hydrogen bonds are complex and remain mostly unclear. This study is focused on the elucidation of the electron transfer in a molecular device consisting of two boron-doped diamond interfaces bound with an aromatic linker and a hydrogen bonding surrogating molecule. The projected local density of states (PLODS) analysis coupled with transmission spectra and current−voltage (I−V) simulations show that hydrogen bonding through electron-donating hydroxyl groups in the aromatic linker facilitates electron transfer, while the electron-withdrawing carboxyl group inhibits electron transfer across the junction. Moreover, slight variations in the geometry of hydrogen bonding lead to significant changes in the alignment of the energy levels and positions of the transmission modes. As a result, we observe the switching of the electron transport mechanism from tunneling to hopping accompanied by a change in the shape of the I−V curves and current magnitudes. These results give important information on the tailoring of the electronic properties of molecular junctions.
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Hotspot of human verbal memory encoding in the left anterior prefrontal cortex
- Çağdaş Topçu
- Victoria Marks
- Krishnakant Saboo
- Michał Lech
- Petr Nejedly
- Vaclav Kremen
- Gregory A. Worrell
- Michał Kucewicz
Background: Treating memory and cognitive deficits requires knowledge about anatomical sites and neural activities to be targeted with particular therapies. Emerging technologies for local brain stimulation offer attractive therapeutic options but need to be applied to target specific neural activities, at distinct times, and in specific brain regions that are critical for memory formation. Methods: The areas that are critical for successful encoding of verbal memory as well as the underlying neural activities were determined directly in the human brain with intracranial electrophysiological recordings in epilepsy patients. We recorded a broad range of spectral activities across the cortex of 135 patients as they memorised word lists for subsequent free recall. Findings: The greatest differences in the spectral power between encoding subsequently recalled and forgotten words were found in low theta frequency (3-5 Hz) activities of the left anterior prefrontal cortex. This subsequent memory effect was proportionally greater in the lower frequency bands and in the more anterior cortical regions. We found the peak of this memory signal in a distinct part of the prefrontal cortex at the junction between the Broca’s area and the frontal pole. The memory effect in this confined area was significantly higher (Tukey-Kramer test, p<0.05) than in other anatomically distinct areas. Interpretation: Our results suggest a focal hotspot of human verbal memory encoding located in the higher-order processing region of the prefrontal cortex, which presents a prospective target for modulating cognitive functions in the human patients. The memory effect provides an electrophysiological biomarker of low frequency neural activities, at distinct times of memory encoding, and in one hotspot location in the human brain.
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Household Ability of Expenditures on Electricity and Energy Resources in the Countries That Joined the EU after 2004
- Krystyna Gomółka
- Piotr Kasprzak
The purpose of the following article is to present the situation of the energy market from a household perspective between 2010 and 2020 in selected EU countries (the group of member states which joined EU after 2004). The selected countries when joining the EU had similar economic indicators and to some extent were similar in other macro-economic situations (personal income, unemployment rate, GDP level and annual growth). This article analyzes the past and current situation of the household ability expenditure on electricity and energy resources (petrol—eurosuper 95 and diesel and natural gas), taking into account price, tax conditions and the real possibility to purchase the analyzed energy sources (based on annual net salaries). The paper includes the conclusions and prospects for the future. The main objective of the study is to determine the ability amount of expenditure on electricity, natural gas and liquid fuels by household in the countries that joined the European Union after 2004. The specific objectives of the work include: the evolution of retail prices of energy sources in those countries and prices of electricity, natural gas and liquid fuels—petrol and diesel oil—in the research period from 2010 to 2020. The element that influences the final price, as assessed in this paper, is the share of taxes and compulsory charges imposed by the EU countries covered in this study. The result of the study presented inter alia that energy consumption structure did not change significantly, electricity prices were steadily growing in the countries under assessment, the use of liquid fuels—petrol and diesel oil—in the countries under study, grew over the study period. Furthermore, prices of fuel fluctuated over the period from 2010 to 2020 and during the COVID-19 pandemic, which broke out in March 2020, but did not cause any significant changes in the prices of energy carriers in the analyzed period, apart from the declines in the prices of eurosuper 95 and diesel.
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How can systems thinking help us in the COVID‐19 crisis?
- Krzysztof Zięba
The COVID-19 pandemic outbreak remains one of the most influential events in the global economy over the recent years. While being primarily public health related, it has a tremendous impact on many other aspects, including business management. Many businesses were forced to introduce rapid changes to their business models in order to survive. The aim of this paper is to show the complexity and interrelations of changes triggered by COVID-19 outbreak. Understanding of this complexity is crucial for developing business resilience to similar events in the future. The paper uses systems thinking approach to analyze influence of COVID-19 pandemic on business operations and to show the importance of the proper government response to the COVID-19 crisis. A causal loop diagram is used to show the complicated mechanisms behind the impact of pandemic on several aspects of business operation and manage- ment. Perceptions of some variables play more important roles than actual variables, and it often requires more than one actor to solve a particular problem. Adaptive business management may prove to be a particular challenge for small business owners. The paper provides useful insights into the complex nature of contemporary business operation and management in the wake of a major epidemiological crisis. It may contribute to a better understanding of important factors that often tend to be disregarded and not paid enough attention to. It offers food for thought not only for academics, but also to business owners/managers, aware of the complexity of contemporary world and to government-level decision-makers.
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How can the work environment be redesigned to enhance the well-being of individuals with autism?
- Michał Tomczak
Purpose – This article examines the opportunities to create optimal conditions for individuals with autism, to work successfully within the contemporary workplace and improve their well-being. These opportunities arise from digital technology (DT) development, enabling the work environment to be remodeled by providing new possibilities and ways of working. The author discusses both technology-based as well as non-technological accommodations supporting overcoming the workplace challenges faced by employees with autism. Design/methodology/approach – A qualitative research was conducted with the use of in-depth interviews with 21 individuals with expertise in the field. Findings – Possible technology-based work environment modifications and non-technological managerial practices facilitating work integration and the long-term well-being of individuals with autism were proposed. These solutions address four main problems: (1) effective communication; (2) time management, task prioritizing, and organization of work; (3) stress management and emotion control; and (4) sensory sensitivity. Practical implications – Proposed solutions include primarily the wide usage of electronic mediated forms of communicating based on non-direct and non-verbal contact; a flexible approach towards work organization; accurate stress monitoring systems; and an individualized approach toward office space arrangements limiting external stimuli. Originality/value – All this could lead not only to an increase in employment in individuals on the autism spectrum but also influence the improvement of the job performance of already employed. Modifications introduced could improve the long-term well-being of all employees, both with autism and neurotypical ones.
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How does climate change affect ice formation and presence in rivers, lakes and oceans, as well as its impact on infrastructure
- Knut Alfredsen,
- Robert Bridges
- Hayo Hendrikse
- Knut Vilhelm Høyland
- Tomasz Kolerski
- Matti Leppäranta,
- Lu Peng
- Xinlei Guo,
Ice season in rivers, lakes, seas and oceans is sensitive to climate change due to the high homologous temperature. Two vital aspects of the predicted climate change are increasing average air temperature and increasing variability in the weather. These cause delayed formation of ice, thinner ice and shorter duration of seasonal ice covers, the geographical ice margin to move further away from the equator, the perennial ice to become thinner and decrease in extent, and as a result the fraction of first-year ice becomes higher. But, because of the larger weather variability, the severity of extreme events may not be reduced. In this article we discuss how ice in surface waters is affected by climate change and discuss some practical consequences for adapting our societies to these changing ice conditions.
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How high-tech solutions support the fight against IUU and ghost fishing: a review of innovative approaches, methods, and trends
- Zuzanna Klawikowska
- Tomasz Ujazdowski
- Michał Grochowski
- Robert Piotrowski
Illegal, Unreported, and Unregulated fishing is a major threat to human food supply and marine ecosystem health. Not only is it a cause of significant economic loss but also its effects have serious long-term environmental implications, such as overfishing and ocean pollution. The beginning of the fight against this problem dates since the early 2000s. From that time, a number of approaches and methods have been developed and reported. A key role in this topic is played by machine learning algorithms which exploit data provided by classical and high-tech sensors, devices and systems such as for example: CCTV, onboard cameras placed on autonomous vehicles, Global Positioning Systems, radars, Automatic Identification Systems, Vessel Monitoring Systems, or Coastal Surveillance Systems. The main objective of this paper is to provide the reader with knowledge about the scale of this phenomenon, methods to tackle the issue, and the current state of research on the subject. This has been achieved through a review of existing approaches that deal with these harmful phenomena by using dedicated artificial intelligence and machine learning tools, as well as the accompanying equipment and devices. In addition, flaws and gaps in current methods, and future directions are disscussed.
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How non-technological innovation saved the day by using ICT
- Julita Wasilczuk
Certainly, the current pandemic situation provides a lot of evidence of the need for non-technological innovations, both in the area of company organization and marketing. Socio-cultural innovations are not less important. Therefore, the role of non-technological innovation during the COVID-19 pandemic is discussed in the sixth chapter. Innovations supported by digital solutions have become a silent heroes for many companies as they struggle with the consequences of the pandemic. New distribution and promotion channels allowed for the continuation of sales during the lockdown. Organizational changes in the functioning of enterprises also played an important role, primarily in the area of work that was transferred to homes. Entrepreneurs, forced to use ICT technologies, have rapidly accelerated their digital transformation. The chapter cites the results of the latest research and reports on the functioning of enterprises during the pandemic, as well as literature relating to crisis management and resilience.
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How to Meet the Green Deal Objectives—Is It Possible to Obtain 100% RES at the Regional Level in the EU?
- Bartłomiej Igliński
- Michał Pietrzak
- Urszula Kiełkowska
- Mateusz Skrzatek
- Artur Gajdos
- Anas Zyadin
- Karthikeyan Natarajan
The subject matter discussed in the article concerns the problem of the energy transformation of the European Union (EU) countries. In the case of the EU, the energy transformation has specific characteristics due to formal legal and institutional provisions. This means that the member states are obliged to implement the adopted Community Energy Strategy, which was defined under the European Green Deal. According to the EU policy, all member states are to have cli-mate-neutral and zero-gas-emission economies by 2050. The energy transformation is to be largely based on the diversification of the energy sources used, with a dominance of renewable energy sources (RES). The article presents a research problem, where the question was asked whether achieving climate-neutral energy independence based solely on RES is possible at the regional level. It seems that the positive answer is an important argument in the discussion about the possibility of all member states achieving the goals set under the European Green Deal. Additionally, stating the possibility of energy independence from RES for a selected re-gion is an important argument to promote just and bottom-up initiatives in order to carry out the energy transformation more effectively. The assessment of the energy potential from re-newable sources at the regional level was carried out on the example of a selected NUTS 2 re-gion, the Greater Poland Voivodeship in Poland. The main objective of the study is to analyze the possibility of obtaining independence from RES by the selected Greater Poland Voivodeship. The implementation of the objective consists of determining the energy potential from RES in the Voivodeship under study on the basis of the methods of a geographic information system (GIS). GIS methods were selected due to the fact that they allow for the spa-tial positioning of point, line, and surface structures in relation to the potential of RES, thus en-suring high accuracy of the obtained estimates. The analysis carried out in the study shows that the technical potential of RES in the Greater Poland Voivodeship is higher than the current elec-tricity and heat usage. This means that by focusing solely on RES in the region, the Greater Po-land Voivodeship can fully meet the energy demand thanks to its green resources. It should be emphasized that the Greater Poland Voivodeship is one of the coal-dependent regions in Poland that has already prepared a structured plan of just transformation.
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How to Sort Them? A Network for LEGO Bricks Classification
- Tomasz Boiński
- Konrad Zawora
- Julian Szymański
LEGO bricks are highly popular due to the ability to build almost any type of creation. This is possible thanks to availability of multiple shapes and colors of the bricks. For the smooth build process the bricks need to properly sorted and arranged. In our work we aim at creating an automated LEGO bricks sorter. With over 3700 different LEGO parts bricks classification has to be done with deep neural networks. The question arises which model of the available should we use? In this paper we try to answer this question. The paper presents a comparison of 28 models used for image classification trained to classify objects to high number of classes with potentially high level of similarity. For that purpose a dataset consisting of 447 classes was prepared. The paper presents brief description of analyzed models, the training and comparison process and discusses the results obtained. Finally the paper proposes an answer what network architecture should be used for the problem of LEGO bricks classification and other similar problems.
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Human emotion recognition with biosignals
- Wioleta Szwoch
This chapter presents issues in the field of affective computing. Basic preliminary information for the recognition of emotions is given and models of emotions, various ways of evoking emotions, as well as their theoretical foundations are discussed. The particular attention is given to the use of physiological signals in recognizing emotions. This subject is outlined further below by presenting selected biosignals, their relationship to emotions and their use in emotion recognition. Related problems, methods and algorithms are presented and applications, along with the possible further research directions reviewed.
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Human System Interaction in Review: Advancing the Artificial Intelligence Transformation
- Daswin De Silva
- Rashmika Nawaratne
- Jacek Rumiński
- Aleksander Malinowski
- Milos Manic
The industrial advancement of human society has been fundamentally driven by diverse ‘systems’ that facilitate ‘human interaction’ within physical, digital, virtual, social and artificial environments, and upon the hyper-connected layers of system-system interactions across these environments. The research and practice of Human System Interaction (HSI) has undergone exponential development due to the enhanced capabilities, increased efficiencies and decreased costs of digitalization. Primarily driven by its unique capacity for information persistence, digitalization is now leading us into a nexus of transition where HSI is being transformed by Artificial Intelligence (AI). AI has leveraged the data and information amassed by digitalization to learn, reason, predict, optimize and thereby augment both human-system interaction and system-system interaction, within and across all hyper-connected environments noted above. In this paper, we review this evolution of HSI and contribute towards its future directions by articulating the AI transformation strategy for this nexus of transition into a Human-AI-System Interaction. The paper begins with a review of HSI that focuses on developments in the past 15 years, followed by the AI transformation strategy which comprises of the primary configurations for Human-AI-System Interaction, the current capabilities of AI, a lifecycle approach for the design, development and deployment of an AI solution and the ethical implications of AI in HSI.
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Hybrid cross-linked chitosan/protonated-proline:glucose DES membranes with superior pervaporation performance for ethanol dehydration
- Roberto Castro-Muñoz
- Emilia Gontarek-Castro
- Jakub Karczewski
- René Cabezas
- Gastón Merlet
- Claudio Araya-Lopez
- Grzegorz Boczkaj
This work explores a protonated L-proline:glucose (molar ratio 5:1) deep eutectic solvent (DES) in fabricating biopolymer membranes utilizing chitosan (CS). Initially, the miscibility of CS and DES to prepare homogeneous dense blend membranes has been investigated. Different techniques, such as scanning electron microscopy, contact angle (CA), atomic force microscopy (AFM), Fourier transformed infrared spectroscopy (FTIR) and swelling degree (uptake), were used to characterize the structure of the resulting membranes. Within the pervaporation performance for ethanol dehydration, Arrhenius and mass transfer analysis were analysed in detail. Interestingly, the addition of DESs provided superior performance to crosslinked CS: DES membranes compared with the ones lacking DES. Based on the morphology and properties observed, this new concept of CS-based membranes can be alternatively applied in other solvent separations requiring hydrophilic membranes.
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Hybrid no-signaling-quantum correlations
- Michał Banacki
- Piotr Mironowicz
- Ravishankar Ramanathan
- Paweł Horodecki
Fundamental investigations in non-locality have shown that while the no-signaling principle alone is not sufficient to single out the set of quantum non-local correlations, local quantum mechanics and no-signaling together exactly reproduce the set of quantum correlations in the two-party Bell scenario. Here, we introduce and study an intermediate hybrid no-signaling quantum set of non-local correlations that we term HNSQ in the multi-party Bell scenario where some subsystems are locally quantum while the remaining subsystems are only constrained by the no-signaling principle. Specifically, the set HNSQ is a super-quantum set of correlations derived from no-signaling assemblages by performing quantum measurements on the trusted subsystems. We show that in contrast to the set NS of no-signaling behaviors, there exist extreme points of HNSQ in the tripartite Bell scenario that admit quantum realization. As a tool for optimization over the set HNSQ, we introduce an outer hierarchy of semi-definite programming approximations to the set following an approach put forward by Doherty–Parrilo–Spedalieri. We perform an extensive numerical analysis of the maximal violation of the facet Bell inequalities in the three-party binary input–output scenario and study the corresponding self-testing properties. In contrast to the usual no-signaling correlations, the new set allows for simple security proofs of (one-sided)-device-independent applications against super-quantum adversaries.
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Hybrid systems using hydrodynamic cavitation/ultrasound/Fenton processes for effective treatment of wastewater
- Vividha Landge
- Vikas S. Hakke
- Sneha Korpe
- P. Venkateswara Rao
- Shirish H. Sonawane
- Shriram Sonawane
- Grzegorz Boczkaj
The present situation of rapid growth in industrialization generates complex recalcitrant pollutants that are challenging to degrade by conventional wastewater treatment processes. The new generation pollutants such as non-metals in cosmetics or household cleaning chemicals and radioactive compounds which are recalcitrant are the emerging threat to the ecosystem. The headstrong micro and macro pollutants present in wastewater are found to be very difficult to mineralize. The known chemical & biological treatments have a limited range of applicability. The conventional methods such as mechanical agitation, coagulation, filtration, sedimentation, etc. are all time and energy-consuming processes. Energy intensive processes the exploitation of emerging technologies like sonocatalysis, photocatalysis, advanced oxidation processes in combination with cavitation (either ultrasonic cavitation or hydrodynamic cavitation), new generation adsorbents such as hydrogel; photoactive compounds, and many more need to be explored individually or in combination to get the end-to-end solution on the wastewater problem. The need for the hybrid system which is technically & economically feasible for getting efficient pollutant separation from the effluents is a colossal requirement. The chapter includes a representation of some of the attempts made to develop hybrid wastewater treatment. The combination of conventional methods such as the adsorption process in assistance with cavitation and the Fenton process to improve the removal efficiency is described with case studies. The chapter includes the case studies of wastewater treatment using the individual and combined effects of all three methods for wastewater treatment. The efficiency and effectiveness of the process have been discussed followed by the future scope & potential application of the process.
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Hybridized Space-Vector Pulsewidth Modulation for Multiphase Two-Level Voltage Source Inverter
- Arkadiusz Lewicki
- Charles Ikechukwu Odeh
- Dmytro Kondratenko
- Marcin Morawiec
In space vector pulsewidth modulation (SVPWM) algorithms for multiphase two-level voltage source inverters (VSI), the components of active vectors in all orthogonal spaces have to be calculated within the processor and stored in its memory. These necessitate intensive computational efforts of the processor and large memory space. This article presents a hybridized SVPWM for multiphase two-level VSI. In this algorithm, elements of the vector coefficient inverse matrix are calculated once outside the inverter processor and treated as constant values; this reduces the computational efforts of the processor and memory space. This scheme reverses the computational steps used in classical SVPWM. Arbitrarily pre-selected active vectors (for any position and amplitude of the reference vectors) with durations determined using classical SVPWM concept are utilized. The durations of switching vectors are analyzed and the switching sequences in individual inverter phases are optimized to reduce the number of commutations. This approach demonstrates that resignation from classical analytical method in multiphase two-level VSI enables the creation of simplified modulation algorithm. This modulation strategy enables an independent generation of multiple output voltage vectors with independent rotating speed, lengths, and positions. Experimental validation of the algorithm was carried out on two-level five-phase VSI with RL load.
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Hybrydowa koncepcja łagodzenia stromości zmian napięcia du/dt dla wielopoziomowych przekształtników kaskadowych SiC
- Marek Adamowicz
- Janusz Szewczyk
- Zbigniew Krzemiński
W referacie zaproponowano nową hybrydową koncepcję łagodzenia stromości zmian napięcia du/dt w wielopoziomowych przekształtnikach kaskadowych SiC. Proponowana koncepcja polega na wykorzystaniu nietłumionego filtra du/dt, podatnego na rezonans oraz zastosowaniu w algorytmie sterowania PWM dodatkowych impulsów sterujących tranzystorami SiC MOSFET, wymuszających rezonansowe przełączanie napięcia na wyjściu filtra. Efekt zmniejszenia stromości du/dt w przekształtniku wielopoziomowym uzyskuje się przy wykorzystaniu pojedynczego filtra du/dt, wspólnego dla całej gałęzi fazowej, co pozwala uzyskać kompaktową konstrukcję całego przekształtnika.
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Hydrogels Based on Natural Polymers for Cardiac Applications
- Zuzanna Cemka
- Paweł Szarlej
- Edyta Piłat
- Przemysław Gnatowski
- Maciej Sienkiewicz
- Justyna Kucińska-Lipka
In this work agar- and borax-based hydrogels with and without the addition of poly(vinyl alcohol) (PVA) at different concentrations were synthesized. Hydrogels were modified by the same amount of acetylsalicylic acid (ASA) which exhibits antithrombotic properties. The effect of modification by ASA on the properties of hydrogels was analyzed.
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Hydrogen Storage in Geological Formations—The Potential of Salt Caverns
- Aleksandra Małachowska
- Natalia Łukasik
- Joanna Mioduska
- Jacek Gębicki
Hydrogen-based technologies are among the most promising solutions to fulfill the ze- ro-emission scenario and ensure the energy independence of many countries. Hydrogen is considered a green energy carrier, which can be utilized in the energy, transport, and chemical sectors. However, efficient and safe large-scale hydrogen storage is still challenging. The most frequently used hydrogen storage solutions in industry, i.e., compression and liquefaction, are highly energy-consuming. Underground hydrogen storage is considered the most economical and safe option for large-scale utilization at various time scales. Among underground geological formations, salt caverns are the most promising for hydrogen storage, due to their suitable physicochemical and mechanical properties that ensure safe and efficient storage even at high pressures. In this paper, recent advances in underground storage with a particular emphasis on salt cavern utilization in Europe are presented. The initial experience in hydrogen storage in underground reservoirs was discussed, and the potential for worldwide commercialization of this technology was analyzed. In Poland, salt deposits from the north-west and central regions (e.g., Rogóźno, Damasławek, Łeba) are considered possible formations for hydrogen storage. The Gubin area is also promising, where 25 salt caverns with a total capacity of 1600 million Nm3 can be constructed.
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Hydrologia obszarów miejskich... opowiedziana inaczej
- Katarzyna Weinerowska-Bords
Zapraszam Czytelników do wspólnej podróży i swoistej nieformalnej rozmowy na temat potrzeby uważności i czujności w pracy inżyniera. Zabawimy się w detektywów i niejako z lupką w dłoni pochylimy się nad pozornie dobrze znanymi procedurami obliczania ilości wód opadowych, nad naszymi inżynierskimi „oczywistościami” i poszukamy pęknięć w tej na pozór dobrze rozpoznanej całości. Zapytamy, co można zrobić lepiej i gdzie tkwią potencjalne pułapki, w które nieświadomie wpadamy, gdy tracimy uważność. Książka przeznaczona jest przede wszystkim dla studentów inżynierii środowiska, ale może się także spodobać innym Czytelnikom, zajmującym się zagadnieniami obliczania ilości wód opadowych, którym nie jest obojętne, czy wyniki własnych obliczeń mają jakieś odzwierciedlenie w rzeczywistości, czy też niekoniecznie…
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Hydrological Dry Periods versus Atmospheric Circulations in the Lower Vistula Basin (Poland) in 1954–2018
- Arkadiusz Bartczak
- Andrzej Araźny
- Michał Krzemiński
- Rafał Maszewski
The paper discusses the impact of atmospheric circulation on the occurrence of droughts. The research in-cludes mean monthly discharges for 7 rivers in 1954-2018. Dry periods were determined with Standardised Streamflow Indices (SSI-12). Additionally, the circulation type calendar for Central Poland was used to determine the atmospheric circulation indices: western zonal (W), southern meridional (S) and cyclonicity (C). The analyses indicated a variation in the duration and intensity of droughts in the rivers. 2014-2017 was the driest period with the lowest SSI-12 for most rivers and the highest number of extremely dry months. The advection of air from the West and the South prevailed and anticyclonic synoptic situations dominated over the cyclonic types. Drought spells occurred at a dominance of anticyclonic circulation, with the inflow of air from the North and with increased western zonal circulation.
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Hydrothermal modification of TiO2 nanotubes in water and alkali metal electrolytes (LiNO3, NaNO3, KNO3) – Direct evidence for photocatalytic activity enhancement
- Mariusz Wtulich
- Mariusz Szkoda
- Grzegorz Gajowiec
- Kacper Jurak
- Grzegorz Trykowski
- Anna Lisowska-Oleksiak
The influence of hydrothermal annealing (HA) of TiO2 nanotubes (TiO2-NTs) in various baths (H2O, LiNO3, NaNO3, KNO3 performed for 4 h, 24 h, 64 h), on their photocatalytic and photoelectrocatalytic properties, was studied. The use of electrolytes was to enable the monitoring of photoactivity changes as a result of the expected impact on the population of hydroxyl groups on the surface. The assumption turned out to be correct and it was proved that the presence of Li+, Na+ or K+ does not allow achieving the same increases in photoactivity as observed for water. Modified samples exhibit significantly decreased F, P and carbon containing species. The length of the HA annealing time considerably affected the geometry of the nanotubes: eliminated clusters, changing the tilting angle of nanotubes, the wall thickness and inter-nanotube distance. Morphology changes due to HA treatment were associated with the interference phenomenon recorded as maximum in the Vis range. HA treatment in water brings about the most photoactive and photoelectroactive material characterized with minor modification in the optical bandgap and position of the flat bad potential. The optical energy bandgap values for electrodes containing alkali metals were reduced (up to 2.72 eV) and flat-band potential was shifted towards the anodic direction (up to 0.25 V disparity). However, increased activity as photocatalysts in the methylene blue degradation process and higher photocurrent generation was achieved for samples after modification in distilled water than in electrolytes, but these parameters are still better in comparison to unmodified titania nanotubes. Long-term treatment in water and electrolytes reduced threshold potentials for oxygen evolution reaction. The studies confirmed the effectiveness of the hydrothermal method for obtaining better photocatalytic parameters of TiO2-NTs and indicate that the presence of alkali metals is not favourable for maintaining high photocatalytic parameters.
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Hyperbranched polyethylenimine functionalized silica/polysulfone nanocomposite membranes for water purification
- Vahid Vatanpour
- Maryam Jouyandeh
- Seyed Soroush Mousavi Khadem
- Mohammad Ganjali
- Hiresh Moradi
- Somayeh Mirsadeghi
- Alireza Badiei
- Amin Esmaeili
- Navid Rabiee
- Sajjad Habibzadeh
- Sasan Nouranian
- Krzysztof Formela
- Mohammad Saeb
Hyperbranched polyethyleneimine functionalized silica (PEI-SiO2) nanoparticles with considerable hydrophilicity were synthesized and incorporated into a polysulfone (PSF)/dimethylacetamide (DMA)/polyvinylpyrrolidone (PVP) membrane casting solution in five different ratios to fabricate PEI-SiO2/PSF nanocomposite membranes using nonsolvent-induced phase separation. The hydrophilic PEI-SiO2 nanoparticles were characterized by TEM, FTIR, TGA, and XPS analyses. Morphology, water contact angles, mean pore sizes, overall porosity, tensile strengths, water flux, antifouling and the dye separation performances of the PEI-SiO2/PSF membranes were also studied. The PEI-SiO2 nanoparticles were uniformly dispersed in the PSF-based membranes, where a fall in the water contact angle was observed from 65.4° to 49.7° by addition of 2 wt% nanoparticles. The fouling resistance parameters of the PEI-SiO2/PSF membranes were declined with an increase in the nanoparticle concentration, suggesting the superior hydrophilic nature of the PEI-SiO2 nanoparticles. The permeability of the nanocomposite membranes was increased from 38.5 to 70 L m−2 h−1 bar−1 by incorporation of 2 wt% PEI-SiO2. Finally, improvements were observed in the flux recovery ratio (95.8%), Reactive Green 19 dye rejection (99.6%) and tensile strengths of the PEI-SiO2/PSF membranes over the neat PSF and SiO2/PSF membranes, which were used as controls. The results of this study demonstrate the promising application of PEI-SiO2 nanoparticles in improving the separation and antifouling performances of the PSF membranes for water purification.
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Hyperelastic Microcantilever AFM: Efficient Detection Mechanism Based on Principal Parametric Resonance
- Amin Alibakhshi
- Sasan Rahmanian
- Shahriar Dastjerdi
- Mohammad Malikan
- Karami Behrouz
- Bekir Akgöz
- Ömer Civalek
The impetus of writing this paper is to propose an efficient detection mechanism to scan the surface profile of a micro-sample using cantilever-based atomic force microscopy (AFM), operating in non-contact mode. In order to implement this scheme, the principal parametric resonance characteristics of the resonator are employed, benefiting from the bifurcation-based sensing mechanism. It is assumed that the microcantilever is made from a hyperelastic material, providing large deformation under small excitation amplitude. A nonlinear strain energy function is proposed to capture the elastic energy stored in the flexible component of the device. The tip–sample interaction is modeled based on the van der Waals non-contact force. The nonlinear equation governing the AFM’s dynamics is established using the extended Hamilton’s principle, obeying the Euler–Bernoulli beam theory. As a result, the vibration behavior of the system is introduced by a nonlinear equation having a time-dependent boundary condition. To capture the steady-state numerical response of the system, a developed Galerkin method is utilized to discretize the partial differential equation to a set of nonlinear ordinary differential equations (ODE) that are solved by the combination of shooting and arc-length continuation method. The output reveals that while the resonator is set to be operating near twice the fundamental natural frequency, the response amplitude undergoes a significant drop to the trivial stable branch as the sample’s profile experiences depression in the order of the picometer. According to the performed sensitivity analysis, the proposed working principle based on principal parametric resonance is recommended to design AFMs with ultra-high detection resolution for surface profile scanning.
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Identification of defected sensors in an array of amperometric gas sensors
- Marta Dmitrzak
- Paweł Kalinowski
- Piotr Jasiński
- Grzegorz Jasiński
Purpose Amperometric gas sensors are commonly used in air quality monitoring in long-term measurements. Baseline shift of sensor responses and power failure may occur over time, which is an obstacle for reliable operation of the entire system. The purpose of this study is to check the possibility of using PCA method to detect defected samples, identify faulty sensor and correct the responses of the sensor identified as faulty. Design/methodology/approach In this work, the authors present the results obtained with six amperometric sensors. An array of sensors was exposed to sulfur dioxide at the following concentrations: 0 ppm (synthetic air), 50 ppb, 100 ppb, 250 ppb, 500 ppb and 1000 ppb. The damage simulation consisted in adding to the sensor response a value of 0.05 and 0.1 µA and replacing the responses of one of sensors with a constant value of 0 and 0.15 µA. Sensor validity index was used to identify a damaged sensor in the matrix, and its responses were corrected via iteration method. Findings The results show that the methods used in this work can be potentially applied to detect faulty sensor responses. In the case of simulation of damage by baseline shift, it was possible to achieve 100% accuracy in damage detection and identification of the damaged sensor. The method was not very successful in simulating faults by replacing the sensor response with a value of 0 µA, due to the fact that the sensors mostly gave responses close to 0 µA, as long as they did not detect SO2 concentrations below 250 ppb and the failure was treated as a correct response. Originality/value This work was inspired by methods of simulating the most common failures that occurs in amperometric gas sensors. For this purpose, simulations of the baseline shift and faults related to a power failure or a decrease in sensitivity were performed.
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Identification of Unstable Reference Points and Estimation of Displacements Using Squared Msplit Estimation
- Marek Zienkiewicz
The article presents a new version of the method for estimating parameters in a split functional model, which enables the determination of displacements of geodetic network points with constrained datum. The main aim of the study is to present theoretical foundations of Msplit CD estimation and its basic properties and possible applications. Particular attention was paid to the efficacy of the method in the context of geodetic network deformation analysis and to the robustness properties of the proposed method. The theoretical considerations were verified by means of two computational tests conducted using the Monte Carlo simulation. The obtained results of methods of estimation parameters in a split functional model were compared with the results of classical method of the least squares estimation. The numerical examples provided in the study indicate the basis properties of Msplit CD estimators being determined.
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IEEE Industrial Electronics Society Students and Young Professionals Just After the Pandemic Time [Students and Young Professionals News]
- Marek Jasinski
- Marek Turzyński
- Dmitri Vinnikov
- Andrii Chub
Report on IEEE IES Society student activities in year 2022.
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IFI16 Impacts Metabolic Reprogramming during Human Cytomegalovirus Infection
- Gloria Griffante
- Weronika Hewelt-Belka
- Camilla Albano
- Francesca Gugliesi
- Selina Pasquero
- Sergio Fernando Castillo Pacheco
- Greta Bajetto
- Paolo Ettore Porporato
- Erica Mina
- Marta Vallino
- Christian Krapp
- Martin Roelsgaard Jakobsen
- John Purdy
- Jens Schneider von Deimling
- Santo Landolfo
- Valentina Dell’Oste
- Matteo Biolatti
Cellular lipid metabolism plays a pivotal role in human cytomegalovirus (HCMV) infection, as increased lipogenesis in HCMV-infected cells favors the envelopment of newly synthesized viral particles. As all cells are equipped with restriction factors (RFs) able to exert a protective effect against invading pathogens, we asked whether a similar defense mechanism would also be in place to preserve the metabolic compartment from HCMV infection. Here, we show that gamma interferon (IFN-g)-inducible protein 16 (IFI16), an RF able to block HCMV DNA synthesis, can also counteract HCMV-mediated metabolic reprogramming in infected primary human foreskin fibroblasts (HFFs), thereby limiting virion infectivity. Specifically, we find that IFI16 downregulates the transcriptional activation of the glucose transporter 4 (GLUT4) through cooperation with the carbohydrate-response element-binding protein (ChREBP), thereby reducing HCMV-induced transcription of lipogenic enzymes. The resulting decrease in glucose uptake and consumption leads to diminished lipid synthesis, which ultimately curbs the de novo formation of enveloped viral particles in infected HFFs. Consistently, untargeted lipidomic analysis shows enhanced cholesteryl ester levels in IFI16 KO versus wild-type (WT) HFFs. Overall, our data unveil a new role of IFI16 in the regulation of glucose and lipid metabolism upon HCMV replication and uncover new potential targets for the development of novel antiviral therapies.
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IgG Avidity Test as a Tool for Discrimination between Recent and Distant Toxoplasma gondii Infection—Current Status of Studies
- Lucyna Holec-Gąsior
- Karolina Sołowińska
Toxoplasma gondii, an obligate intracellular protozoan parasite, is the causative agent of one of the most prevalent zoonoses worldwide. T. gondii infection is extremely important from a medical point of view, especially for pregnant women, newborns with congenital infections, and immunocompromised individuals. Thus, an accurate and proper diagnosis of this infection is essential. Among the available diagnostic tests, serology is commonly used. However, traditional serological techniques have certain limitations in evaluating the duration of T. gondii infection, which is problematic, especially for pregnant women. Avidity of T. gondii-specific IgG antibodies seems to be a significant tool for discrimination between recent and distant infections. This article describes the problem of diagnosis of T. gondii infection, with regard to IgG avidity tests. The IgG avidity test is a useful serological indicator of toxoplasmosis, which in many cases can confirm or exclude the active form of the disease. IgG antibodies produced in the recent primary T. gondii infection are of low avidity while IgG antibodies with high avidity are detected in the chronic phase of infection. Furthermore, this paper presents important topics of current research that concern the usage of parasite recombinant antigens that may improve the performance of IgG avidity tests.
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