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Repozytorium publikacji
Politechniki Gdańskiej

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  • Modyfikacja biodegradowalnych poliestrów alifatycznych za pomocą inicjatorów nadtlenkowych
    • Marta Przybysz-Romatowska
    • Józef Haponiuk
    • Krzysztof Formela
    2019 Pełny tekst Tworzywa Sztuczne w Przemyśle

    Czynniki ekologiczne, ekonomiczne oraz większa świadomość społeczeństwa wpływają korzystnie na dynamiczny rozwój bio- degradowalnych materiałów, które sukcesywnie zastępują polimery „konwencjonalne”. Biodegradowalne polimery zarówno ze źródeł odnawialnych, jak i nieodnawialnych wzbudzają duże zainteresowanie wielu jednostek naukowo-badawczych oraz firm, głównie w zakresie ich modyfikacji. W pracy przedstawiono wyniki badań wpływu inicjatorów nadtlenkowych na właściwo- ści mechaniczne poli(ε-kaprolaktonu) (PCL). Badania wykazały, że modyfikacja za pomocą nadtlenków dikumylu (DCP) oraz di-(2-tert-butylo-peroksyizopropylo)benzenu (BIB) wprowadzonych do matrycy polimeru w odpowiednich ilościach prowadzi do poprawy właściwości mechanicznych PCL. W badanych warunkach, najlepszymi właściwościami charakteryzował się PCL mo- dyfikowany za pomocą BIB w ilości 0,5 części wagowych.

  • Modyfikacja biodegradowalnych poliestrów ialifatycznych i ich mieszanin w obecności inicjatorów nadtlenkowych.
    • Aneta Starukiewicz
    • Marta Przybysz-Romatowska
    • Józef Haponiuk
    • Krzysztof Formela
    2019

    Streszczenie Czynniki ekologiczne, ekonomiczne oraz większa świadomość społeczeństwa wpływają korzystnie na dynamiczny rozwój biodegradowalnych materiałów, które sukcesywnie zastępują polimery „konwencjonalne”. Na szczególną uwagę zasługują komercyjnie dostępne poliestry alifatyczne takie jak: poli(kwas mlekowy) (PLA), poli(3-hydroksymaślan) (PHB), oraz poli(ε-kaprolakton) (PCL). Jednakże ich wysoka cena oraz problemy technologiczne związane z właściwościami przetwórczymi, mechanicznymi i termicznymi ograniczają zastosowanych w/w materiałów. W niniejszej pracy omówiono podstawowe założenia projektu pt. „Wpływ struktury inicjatorów nadtlenkowych na mechanizm oraz efektywność dynamicznego sieciowania biodegradowalnych poliestrów alifatycznych oraz ich mieszanin” realizowanego obecnie w Katedra Technologii Polimerów, Wydziału Chemicznego, Politechniki Gdańskiej. Podziękowania Praca została wykonana w ramach projektu PRELUDIUM 15 2018/29/N/ST8/02042 finansowanego przez Narodowe Centrum Nauki

  • Modyfikacje chemiczne Amfoterycyny B i Nystatyny A1
    • Kornelia Skarbek
    2019 Pełny tekst

    W ramach badań, opisanych w niniejszej rozprawie doktorskiej, przetestowano możliwości chemicznej modyfikacji części aminocukrowej aglikonu amfoterycyny B i nystatyny A1. Otrzymano chroniony aglikon AmB, posiadający grupę hydroksylową na atomie węgla C19, który posłużył jako substrat w reakcji substytucji nukleofilowej oraz dehydracyjnej glikozylacji. Opracowano i zoptymalizowano warunki syntezy chronionych pochodnych cukrowych, będących dogodnymi substratami do reakcji z aglikonem makrolidowym. Ponadto zoptymalizowano metodę syntezy koniugatów amfoterycyny B oraz nystatyny A1 z ‘parasolami molekularnymi’, pochodnymi kwasu cholowego oraz opracowano warunki syntezy analogicznych związków z ‘parasolami molekularnymi’, pochodnymi kwasu deoksycholowego. Otrzymano dwanaście nieopisanych koniugatów makrolidów polienowych, które zostały przebadane pod kątem aktywności przeciwgrzybowej i selektywnej toksyczności względem krwinek ludzkich, a wyniki tych badań zostały opublikowane.

  • Moja najpiękniejsza w życiu miłość, instalacja artystyczna, wystawa Gość Inność, Galeria MD_S, Wrocław
    • Patryk Różycki
    2019

    Zjadłem kapustę z grochem i chleb, słuchałem mojej mamy i czekałem na wiadomość od kogoś. Czułem smutek, moje otoczenie było przyciśnięte ciężarem wzroku, czegoś obojętnego we mnie, wrażliwego, nadwrażliwej struny. Powiedziałem mamie, że jest mi smutno i poszedłem do pokoju, wszedłem na łóżko i usiadłem obok taty, zsunąłem moje ciało po materacu i skulony ułożyłem głowę na jego brzuchu. Jasny sweter, uchem słyszałem pracujący żołądek, jego soki, oddech, nosem czułem miłe ciepło i zapach, ten sam, zawsze, zapach mojego taty. Głaskał mnie po głowie, plątał włosy, palcem w uchu, zacząłem płakać. Skulony, z głową na jego brzuchu płakałem, tak bardzo poczułem własny smutek, samotność. Wobec drugiego człowieka moje serce jest zbyt wrażliwe, delikatne, delikatne na wszystko. Tak bardzo potrzebowałem bliskości, bliskości kogoś, kto mnie kocha albo, kto mógłbym mnie pokochać, jeśli by chciał lub gdybym zapytał. Byłem w tym moim płakaniu cichy, z rozmazanymi promieniami żarówki, z zimnem łez na gorących policzkach, łzy szybko wyparowały, roztopiły się jak garstka śniegu na ciepłej dłoni. W tej potrzebie bliskości nagle jestem jakiś nieswój, chciałbym to wszystko lepiej, płaczę, grube łzy, super odczuwalne wrażenia, tulenie się, splatane palce i stopy i ciężar kolan i pleców i zapach włosów, temperatura ciała. I to wszystko jest czyjeś, tak bardzo prywatne, czyjeś, wrażliwe, wzruszające mnie. I gdzieś nagle te ciała stają się malutkimi wysepkami, na które razem wypłynęliśmy, leżymy nago, na naszych pięknych ciałach, w promieniach boskiego słońca, oddychamy miłością. Rodzina już odjechała, na pożegnanie płacz, dziesięć płaczących oczu, czerwonych, z łamiącymi się głosikami. Nie byłem w stanie odprowadzić ich nawet do samochodu, nie miałem siły na rozciągnięte oczekiwanie rozstania, wolałem zerwać to nagle, zrywem, zrywem potraktować ten moment, ten smutek, który kolejny, kolejny dołączył do wielu moich, do wielu we mnie, tak nagle to się stało, d d d drr drrrga drrrgam od Ciebie i od Ciebie i od Ciebie i od Ciebie i od Ciebie też, wybacz mi, drgam, również od siebie, boję się, boję się czegoś, pewnie wiem o tym, mimo to, drgam, z sobą i też z Tobą, trochę, też, może.

  • Molecular Structures of the Phospha-Wittig Reaction Intermediate: Initial Step in the Synthesis of Compounds with a C═P–P Bond as Products in the Phospha-Wittig Reaction
    • Aleksandra Ziółkowska
    • Natalia Szynkiewicz
    • Łukasz Ponikiewski
    2019 ORGANOMETALLICS

    The phospha-Wittig reactivity ofβ-diketiminate titanium(III) complexes with phosphanylphosphido ligands was investigated. The reactions of [MeNacNacTi(Cl){η2-P(SiMe3)-PtBu2}] and [MeNacNacTi(Cl){η2-P(SiMe3)-P(Ph)tBu}] with acetone conducted in toluene solution under mild conditions led to the phospha-Wittig intermediates [{(ArN=C(Me)CHC(Me)=NAr)(C(Me)2O}Ti(Cl){PtBu2-P(SiMe3)C(Me)2O}] (1) and [{(ArN=C(Me)CHC(Me)=NAr) (C-(Me)2O}Ti(Cl){P(Ph)tBu-P(SiMe3)C(Me)2O}] (2). Complexes 1 and 2 were isolated in the crystalline form and characterized for thefirst time. Furthermore, the isolated complexes1and2dissolved in THF solution led to the phospha-Wittig reaction products - phosphanylphosphaalkenes tBu2P−P=C(Me)2(1a) and (Ph)tBuP−P=C(Me)2(2a)

  • Molecularly imprinted polymers applied in capillary electrochromatography and electrophoresis techniques
    • Małgorzata Rutkowska
    • Jacek Namieśnik
    2019

    Molecularly imprinted polymers (MIPs) are synthetic materials with predetermined selectivity for a particular analyte or group of structure-linked chemicals which make them an ideal separation component. The process of developing and applying new types of MIPs in the field of environmental analytical chemistry has been broadly discussedi n many scientific studies in recent years. The use of new types of MIP sorbents as unique sorption materials in the stationary phase in the field of advanced separation techniques is one of the new trends in analytical chemistry practice. The capillary electrophoresis (CE) technique is characterized by high efficiency, low consumption of solvents and selectors, simple instrumentation, as well as short analysis time were applied in practical problem solving in chemical, pharmaceutical, biomedical, food, environmental, etc.. Capillary electrochromatography (CEC) employs the highseparation efficiency of capillary electrophoresis (CE) andhigh selectivity of high performance liquid chromatogra-phy (HPLC). Application of MIP for analytical scale separation in CE and CEC are becoming more popular than in LC nowadays due to the intrinsic character of high separation efficiency and minimized requirement of the amount of MIP template in CE and CEC.The following chapter contains comprehensive information about the application of specific and well defined MIPs in various formats as a sorption medium in CEC and CE separation techniques.

  • Monitoring of lysozyme thermal denaturation by volumetric measurements and nanoDSF technique in the presence of N-butylurea
    • Joanna Krakowiak
    • Magdalena Krajewska
    • Jarosław Wawer
    2019 Pełny tekst JOURNAL OF BIOLOGICAL PHYSICS

    The results of thermal studies of denaturation of hen egg white lysozyme (HEWL) in water and an aqueous solution of N-butylurea (BU) are presented. High-precision densimetric measurements were used to characterize and analyze the changes of the specific volume, v, during temperature elevation. The temperature of the midpoint of protein denaturation was also determined by nanoDSF technique (differential scanning fluorimetry). The densities of lysozyme solutions were measured at temperatures ranging from 298.15 to 353.15 K with an interval of 5 K at atmospheric pressure (0.1 MPa). The concentration of the protein covered the range from 2 to 20 mg per 1 ml of the solution. The optimal range of the concentration for the densimetric measurements was roughly estimated. In the transition region, the structural changes of the protein are accompanied by the biggest increase of ν values with temperature. Our measurements show that this effect can be monitored from volumetric data without precise determination of protein concentration. The results prove that a two-state model of denaturation could be used for data interpretation. Contrary to common misconception, the volumetric measurements suggest that the denatured protein does not necessarily need to be in a fully extended state. In this way, the ‘protein volume paradox’ could be explained. The surface area of the protein remains unchanged and thus the increase of the specific volume of the protein is relatively small. Additionally, the self-stabilizing effect of the protein in BU solution was reported. For the HEWL in pure water, this phenomenon was not observed.

  • Monitoring of odors emitted from stabilized dewatered sludge subjected to aging using proton transfer reaction–mass spectrometry
    • Hubert Byliński
    • Radosław Barczak
    • Jacek Gębicki
    • Jacek Namieśnik
    • Radoslaw Barczak
    2019 Pełny tekst ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH

    One of the potential emission sources of odorous compounds from wastewater treatment plants is sludge processing. The odorous compounds released from dewatered sludge can result in odor nuisance. This study concerns the use of flux hood chamber combined with proton transfer reaction—time of flight—mass spectrometry (PTR-MS) technique for periodical monitoring of odorous compounds emitted from aged, stabilized dewatered sludge samples from 2 different wastewater treatment plants located in Pomeranian Voivodeship, Poland. Based on determined concentration of the chemical compounds and olfactory threshold values, theoretical odor concentrations (known also as “odor activity value” or “odor index”) were calculated for 17 selected odorous compounds. As a result, sulfur compounds such as diethyl sulphide, dimethyl sulphide, methanethiol, and ethanethiol were estimated as the most significant chemical compounds responsible for malodorous effect (average results, e.g., methanethiol, 178 ou/m3; diethyl sulphide, 184 ou/m3). Based on Pearson correlation coefficient, we revealed a correlation between odorous substances emitted from aged, stabilized dewatered sludge cakes. It was revealed that stabilized dewatered sludge still possessed significant amount of odorous compounds and applied measurement technique could be used for monitoring of odor concentration level of selected malodorous compounds.

  • Monosubstituted hydrazone β-cyclodextrin derivatives for pH-sensitive complex formation with aromatic drugs
    • Maciej Majdecki
    • Agata Krzak
    • Kamila Sadowska
    • Olga Swiech
    2019 Pełny tekst Journal of Inclusion Phenomena and Macrocyclic Chemistry

    A new and convenient synthetic pathway was developed to produce monosubstituted cyclodextrins with high yields. Each of the β-cyclodextrin derivatives described in this work has an aromatic substituent connected with cyclodextrin core by a pH-sensitive hydrazone linker and a carbon chain. Carbon chains differ in lengths having one or three carbon atoms. The correlation between water solubility and linker length was determined using UV–Vis spectroscopy, while the dependence of hydrazone bond hydrolysis on the electrolyte pH was confirmed by cyclic voltammetry. The pH-dependent complex-formation ability between the hydrazone derivative of cyclodextrin and anthracycline drug was examined by square wave voltammetry. The significantly big solubility and the appropriate pH, at which the hydrolysis of the hydrazone bond occurs, make the newly synthesized derivatives attractive for pharmaceutical and medical applications.

  • Monument of History in Gdynia - Problems with Protection of the Main Representative Axis of the City
    • Maria Sołtysik
    2019 Pełny tekst Ochrona Dziedzictwa Kulturowego

    The spatial idea of the main representative axis was presented in 1938 in the project of the Representative District of Gdynia and partly realised in 1938-1939. Although the whole area was included in the Gdynia's Monument of History, now its spatial integration is on thread by the controversial current development plans

  • Morphology, Photocatalytic and Antimicrobial Properties of TiO2 Modified with Mono- and Bimetallic Copper, Platinum and Silver Nanoparticles
    • Izabela Wysocka
    • Ewa Kowalska
    • Jacek Ryl
    • Grzegorz Nowaczyk
    • Anna Zielińska-Jurek
    2019 Pełny tekst Nanomaterials

    Noble metal nanoparticles (NMNPs) enhanced TiO2 response and extended its activity under visible light. Photocatalytic activity of TiO2 modified with noble metal nanoparticles strongly depends on the physicochemical properties of NMNPs. Among others, the differences in the size of NMNPs seems to be one of the most important factors. In this view, the effect of the metal’s nanoparticles size, type and amount on TiO2 photocatalytic and biocidal activity was investigated. TiO2 modified with mono- and bimetallic nanoparticles of Pt, Cu and Ag were prepared using chemical and thermal reduction methods. Obtained nanocomposites were characterized using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and diffuse-reflectance spectroscopy (DR/UV-Vis) techniques. The photocatalytic activity was examined in 2-propanol oxidation and hydrogen generation processes. The mechanism of modified TiO2 excitation was evaluated in action spectrum measurements during phenol oxidation. A possibility of using less energy-consuming light sources as a set of light-emitting diodes (LEDs) selected based on action spectrum results was examined. It was found that the differences in NMNPs size were the result of the reduction method. Moreover, coupling with a second metal strongly affected and differentiated the photocatalytic and biocidal activity of the obtained TiO2-based photocatalysts.

  • Morphology, surface properties and photocatalytic activity of the bismuth oxyhalides semiconductors prepared by ionic liquid assisted solvothermal method
    • Aleksandra Bielicka-Gieldon
    • Patrycja Wilczewska
    • Anna Malankowska
    • Karol Szczodrowski
    • Jacek Ryl
    • Anna Zielińska-Jurek
    • E.m. Siedlecka
    2019 SEPARATION AND PURIFICATION TECHNOLOGY

    This is the first report of the effect of the ILs cation type (imidazolium, pyridinium and pyrrolidinium) on the morphology, surface properties and photoactivity of BiOX semiconductors type obtained by solvothermal method in glycerol. The various ionic liquids (IL) cation type as a halogen source and templating agent for the synthesis of the bismuth oxyhalides nanoparticles has been systematically investigated. The role of ILs in synthesis of the semiconductors was loosening of the structure and increasing the particle size of semiconductors. It was also found that ILs increased specific surface area and pore volume of bismuth oxyhalides. Rhodamine B and 5-fluorouracil were used as the model contaminates to evaluate the adsorption capacity and photooxidation performance of studied BiOX. Removal of chromium (VI) from acidic solution were demonstrated photoreduction ability of BiOX. Generally the activity of bismuth oxyhalides was better for the samples prepared with ILs, although the increase in activity was different for various ionic liquids. The changes of band gap structure were major causes of the enhanced photocatalytic activity of bismuth oxyhalides with ILs as the halogen source.

  • Mostowa wizytówka Mikołajek
    • Maciej Malinowski
    • Marcin Jeszka
    • Arkadiusz Sitarski
    • Anna Banaś
    2019

    W pracy omówiono nową kładkę dla pieszych nad jeziorem Mikołajskim w Mikołajkach. Przedstawiono aspekty projektowania i wykonawstwa obiektu. Przedstawiono reprezentatywne wyniki badań odbiorowych. Przedstawiono nowatorski i unikatowy w skali Europy system iluminacji obiektu, który jest wizytówka zarówno Mikołajek jak i całego regionu - Mazur.

  • Mountain pass type periodic solutions for Euler–Lagrange equations in anisotropic Orlicz–Sobolev space
    • Magdalena Chmara
    • Jakub Maksymiuk
    2019 Pełny tekst JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS

    Using the Mountain Pass Theorem, we establish the existence of periodic solution for Euler–Lagrange equation. Lagrangian consists of kinetic part (an anisotropic G-function), potential part and a forcing term. We consider two situations: G satisfying at infinity and globally. We give conditions on the growth of the potential near zero for both situations.

  • MOŻLIWOŚCI WYKORZYSTANIA METOD I MODELI PROBABILISTYCZNYCH W PROJEKTOWANIU OKRĘTOWYCH INSTALACJI PAROWYCH
    • Damian Bocheński
    • Dominik Kreft
    2019 Pełny tekst Journal of Polish CIMEEAC

    Artykuł przedstawia możliwości wykorzystania metod i modeli probabilistycznych w projektowaniu okrętowych instalacji parowych w siłowniach spalinowych. Zaproponowano dwie możliwości opisu eksploatacyjnych wydajności kotłów utylizacyjnych oraz eksploatacyjnego zapotrzebowania ciepła. Pierwsza to zastosowanie do opisu rozkładu normalnego, drugą jest zamodelowanie okrętowej instalacji parowej jako systemu masowej obsługi.

  • Możliwości zastosowania oświetlenia dziennego w projektowaniu architektonicznym wnętrz biurowych w Polsce północnej. Badanie możliwości redukcji oświetlenia sztucznego.
    • Marta Waczyńska
    • Justyna Martyniuk-Pęczek
    2019

    Artykuł stanowi analizę możliwości użycia światła dziennego w projektowaniu oświetlenia wnętrz biurowych. Głównym celem badania było wykazanie na ile możliwe jest zastąpienie oświetlenia sztucznego w projekcie światłem dziennym, przy zachowaniu wartości parametrów oświetleniowych wymaganych dla prawidłowego oświetlenia miejsc pracy. Podstawową motywacją do przeprowadzenia badania była wzrastająca rola maksymalizacji wykorzystania światła dziennego, jako głównego źródła oświetlenia pomieszczeń biurowych, ze względu na optymalizację rozwiązań projektu wnętrz w zakresie funkcjonalnym, ekonomicznym i energetycznym.

  • MRI assessment of ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with the presence of central obesity and metabolic syndrome
    • J Pieńkowska
    • B. Brzeska
    • Mariusz Kaszubowski
    • Oliwia Kozak
    • Anna Jankowska
    • Edyta Szurowska
    2019 Pełny tekst Diabetes Metabolic Syndrome and Obesity-Targets and Therapy

    Purpose: Obesity, defined as a body mass index (BMI) exceeding 30 kg/m2, is a serious health problem, which can be called an epidemic on a global scale and is one of the most important causes of preventable death. The aim of this study was to assess ectopic fat accumulation in pancreas, liver and skeletal muscle in patients with obesity, overweight and normal BMI in correlation with metabolic syndrome (MetS). Patients and methods: The study included 267 consecutive patients who underwent a standard clinical assessment with BMI calculation. Ectopic fat accumulation in pancreas, liver, and skeletal muscle was evaluated by magnetic resonance imaging (MRI) using fat-water separated Dixon imaging. MetS was defined according to the criteria modified by the National Cholesterol Education Program Adult Treatment Panel III Guidelines. Central obesity was defined using gender and ethnic-specific values for waist circumference. Results: There was a statistically significant correlation between the degree of steatosis of the assessed organs and BMI value as well as waist circumference ratio, that determined the degree of central obesity. It was found that the most rapid relative fat accumulation was in muscle, then in pancreas and then in liver. Higher steatosis of pancreas, liver, and muscle was demonstrated depending on the number of the satisfied MetS criteria. Conclusion: Knowing that pancreatic fatty disease is a risk factor for MetS, it seems that assessment and monitoring of ectopic fat accumulation may have important clinical implications and may be used in the prediction of metabolic risk and its early prevention.

  • MRM–MS of marker peptides and their abundance as a tool for authentication of meat species and meat cuts in single-cut meat products
    • Katarzyna Nalazek-Rudnicka
    • Ilona Edyta Kłosowska-Chomiczewska
    • Andrzej Wasik
    • Adam Macierzanka
    2019 Pełny tekst FOOD CHEMISTRY

    The abundance of protein markers in different types of meat cuts was explored in the context of authentication of raw meat (pork, beef and chicken) and processed meat products. Peptides originating from myoglobin (Mb) and myosin (My) were analyzed using multiple reaction monitoring mass spectrometry (MRM–MS). Analytical protocol was optimized for good repeatability (CV < 10%) and high sensitivity. The MS signal intensity of Mb marker peptides in raw pork depended significantly on the cut type (e.g. ham vs knuckle). Importantly, a similar pattern in the abundance of the marker peptides was found for processed meat products made of different types of pork cuts, despite the food processing applied. This suggests the protocol can be used for authentication of raw pork cuts and processed products made of different cuts of pork. More uniform contents of Mb markers were found in raw beef cuts, and for My markers in raw chicken cuts.

  • Multi-agent large-scale parallel crowd simulation with NVRAM-based distributed cache
    • Artur Malinowski
    • Paweł Czarnul
    2019 Journal of Computational Science

    This paper presents the architecture, main components and performance results for a parallel and modu-lar agent-based environment aimed at crowd simulation. The environment allows to simulate thousandsor more agents on maps of square kilometers or more, features a modular design and incorporates non-volatile RAM (NVRAM) with a fail-safe mode that can be activated to allow to continue computationsfrom a recently analyzed state in case of a failure. We show results for an evacuation scenario for an areaof up to 6 km2in a district of Gdansk, Poland, performed on two clusters, one with hardware simulationof NVRAM. We have shown a very small overhead of using NVRAM compared to the RAM only solutionand an overhead of 20% with the fail-safe mode on using NVRAM, shown up to 30 000 agents and up to25 000 iterations of the simulation. We also show the benefit of using NVRAM for file synchronizationwith a slow growth of the execution time while increasing the map size. We then present how the fre-quency of visualization affects execution time and very good scaling of the proposed solution in a clusterenvironment for more than 650 processes and 60 000 agents.

  • Multibody models for gait analysis
    • Wiktoria Wojnicz
    • Bartłomiej Zagrodny
    • Michał Ludwicki
    • Jerzy Mrozowski
    • Jan Awrejcewicz
    • Edmund Wittbrodt
    2019 Pełny tekst

    The aim of this study was to create multibody biomechanical models to analyze a normal gait of the human. Proposed models can be used to identify joint moments of the lower limbs during normal gait in the single and double support phases. Applying Newton-Euler formulation, following planar models were developed: 1) a mathematical 6DOF model describing a gait in the sagittal plane of the body for single support phase and double support phase; 2) a mathematical 7DOF model describing a gait in the sagittal plane of the body for single support phase and double support phase; 3) a mathematical 7DOF model describing a gait in the frontal plane of the body for single support phase and double support phase. Proposed mathematical models can be applied to solve a forward dynamic task or inverse dynamic task. A validation of these models had been performed by comparing results measured over examination of normal human gait and results calculated by solving an inverse dynamic task.

  • Multi-Criteria Knowledge-Based Recommender System for Decision Support in Complex Business Processes
    • Aleksandra Revina
    • Nina Rizun
    2019 Pełny tekst

    In this paper, we present a concept of a multi-criteria knowledge-based Recommender System (RS) designed to provide decision support in complex business process (BP) scenarios. The developed approach is based on the knowledge aspects of Stylistic Patterns, Business Sentiment and Decision-Making Logic extracted from the BP unstructured texts. This knowledge serves as an input for a multi-criteria RS algorithm. The output is prediction of the BP complexity, based on which the algorithm modifies the type and the way of decision support, ranging from full to minimal automation. We show how the algorithm can be applied in the real-life scenarios by the example of the IT ticketing case study. We also evaluate the BP complexity prediction quality using both quantitative (data-based) and qualitative (interview-based) approach in the case study

  • Multi-Fidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
    • Yiran Song
    • Qingsha Cheng
    • Sławomir Kozieł
    2019 Pełny tekst SENSORS

    In order to minimize the number of evaluations of high-fidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computational-efficient multi-fidelity local surrogate-model optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multi-fidelity coarse models and polynomial interpolation to construct a series of local surrogate models. In the optimization process, local region modeling and optimization are performed iteratively. A judgment factor is introduced to provide information for local region size update. The last local surrogate model is refined by space mapping techniques to obtain the optimal design with high accuracy. The operation and efficiency of the approach are demonstrated through design of a bandpass filter and a compact ultra-wide-band (UWB) multiple-in multiple-out (MIMO) antenna. The response of the optimized design of the fine model meet the design specification. The proposed method not only has better convergence compared to an existing local surrogate method, but also reduces the computational cost substantially

  • Multifrequency Nanoscale Impedance Microscopy (m-NIM): A novel approach towards detection of selective and subtle modifications on the surface of polycrystalline boron-doped diamond electrodes
    • Artur Zieliński
    • Mateusz Cieślik
    • Michał Sobaszek
    • Robert Bogdanowicz
    • Kazimierz Darowicki
    • Jacek Ryl
    2019 Pełny tekst ULTRAMICROSCOPY

    In this paper, we describe the modification of Nanoscale Impedance Microscopy (NIM), namely, a combination of contact-mode atomic force microscopy with local impedance measurements. The postulated approach is based on the application of multifrequency voltage perturbation instead of standard frequency-by-frequency analysis, which among others offers more time-efficient and accurate determination of the resultant impedance spectra with high spatial resolution. Based on the impedance spectra analysis with an appropriate electric equivalent circuit, it was possible to map surface resistance and contact capacitance. Polycrystalline heavy boron-doped diamond (BDD) electrodes were the research object. Recent studies have shown that the exposure of such electrodes to oxidizing environment may result in the modification of termination type, and thus it is a key factor in describing the electric and electrochemical properties of BDD. We have successfully applied multifrequency NIM, which allowed us to prove that the modification of termination type is selective and occurs with different propensity on the grains having specific crystallographic orientation. Furthermore, our approach enabled the detection of even subtle submicroscopic surface heterogeneities, created as a result of various oxidation treatments and to distinguish them from the surface heterogeneity related to the local distribution of boron at the grain boundaries.

  • Multimedialny system nadzoru dla straży granicznej – projekt STRADAR
    • Marek Blok
    • Bartosz Czaplewski
    • Sylwester Kaczmarek
    • Jacek Litka
    • Magdalena Młynarczuk
    • Marcin Narloch
    • Maciej Sac
    2019 Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne

    STRADAR jest systemem nadzoru przeznaczonym do wspierania działań operacyjnych morskiej straży granicznej, umożliwiającym zbieranie, przetwarzanie i udostępnianie informacji i danych pochodzących z takich sensorów, jak radary, kamery wideo, AIS, GPS, aparaty fotograficzne oraz z połączeń audio, wiadomości SMS, plików i notatek. Informacje te mogą być udostępniane na bieżąco oraz archiwalnie z synchronizacją zdarzeń lub bez synchronizacji. Forma i sposób prezentacji jest konfigurowany przez personel w zależności od aktualnych potrzeb. Na wieloekranie stanowiska wizualizacji zadań można prezentować jednocześnie wiele zadań.

  • MULTIMODALNE POMIARY DRGAŃ STRUNY
    • Marta Stefaniak
    • Witold Nosorowski
    2019 Pełny tekst Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

    W artykule zostały przedstawione badania drgań struny zrealizowane przy użyciu szybkich kamer wizyjnych, mikrofonu oraz akcelerometru. Obiektem badań były instrumenty muzyczne. Opisano zjawiska zachodzące w instrumencie podczas tworzenia się i wydobywania z niego dźwięku. Celem pracy było zbadanie różnic w wynikach otrzymanych poprzez pomiary wykonane z użyciem zróżnicowanych reprezentacji obrazowych i sygnałowych. Zaproponowano sposób pobudzania instrumentu, który pozwolił na wykonywane badań w sposób powtarzalny. Opisano metodologię wykonanych pomiarów oraz algorytm do analizy pomiarów wykonanych metodą optyczną, który umożliwił przetworzenie zarejestrowanego obrazu na sygnał foniczny. Na koniec zaprezentowano otrzymane wyniki z wszystkich modalności oraz wnioski z analiz.

  • Multi-objective optimization of microextraction procedures
    • Marta Bystrzanowska
    • Marek Tobiszewski
    2019 Pełny tekst TRAC-TRENDS IN ANALYTICAL CHEMISTRY

    Optimization of extraction process requiresfinding acceptable conditions for many analytes and goodperformance in terms of process time or solvent consumption. These optimization criteria are oftencontradictory to each other, the performance of the system in given conditions is good for some criteriabut poor for others. Therefore, such problems require special assessment tools that allow to combinethese contradictory criteria into single score tofind“the golden mean”. This contribution summarizes theexamples of approaches that are used for multi-objective optimization. Derringer's desirability functionsare used for large variety of microextraction techniques optimizations. Finding Pareto-optimal solutionsallows to easily separate conditions that are definitely not acceptable. Alternative solution is applicationof multi-criteria decision analysis for microextraction processes optimization.

  • MULTI-OBJECTIVE OPTIMIZATION PROBLEM IN THE OptD-MULTI METHOD
    • Wioleta Błaszczak-bąk
    • Anna Sobieraj-Żłobińska
    • Michał Kowalik
    2019 Pełny tekst Metrology and Measurement Systems

    New measurement technologies, e.g. Light Detection And Ranging (LiDAR), generate very large datasets. In many cases, it is reasonable to reduce the number of measuring points, but in such a way that the datasets after reduction satisfy specific optimization criteria. For this purpose the Optimum Dataset (OptD) method proposed in [1] and [2] can be applied. The OptD method with the use of several optimization criteria is called OptD-multi and it gives several acceptable solutions. The paper presents methods of selecting one best solution based on the assumptions of two selected numerical optimization methods: the weighted sum method and the "-constraint method. The research was carried out on two measurement datasets from Airborne Laser Scanning (ALS) and Mobile Laser Scanning (MLS). The analysis have shown that it is possible to use numerical optimization methods (often used in construction) to obtain the LiDAR data. Both methods gave different results, they are determined by initially adopted assumptions and – in relation to early made findings, these results can be used instead of the original dataset for various studies.

  • Multiresolution analysis and adaptive estimation on a sphere using stereographic wavelets
    • Bogdan Ćmiel
    • Karol Dziedziul
    • Natalia Jarzębkowska
    2019 Pełny tekst NONLINEAR ANALYSIS-THEORY METHODS & APPLICATIONS

    We construct an adaptive estimator of a density function on d dimensional unit sphere Sd (d ≥ 2), using a new type of spherical frames. The frames, or as we call them, stereografic wavelets are obtained by transforming a wavelet system, namely Daubechies, using some stereographic operators. We prove that our estimator achieves an optimal rate of convergence on some Besov type class of functions by adapting to unknown smoothness. Our new construction of stereografic wavelet system gives us a multiresolution approximation of L2(Sd) which can be used in many approximation and estimation problems. In this paper we also demonstrate how to implement the density estimator in S2 and we present a finite sample behavior of that estimator in a numerical experiment.

  • Mury oporowe z gruntu zbrojonego z przekładkami z keramzytu
    • Grzegorz Horodecki
    • Anita Biłanicz
    • Karolina Smentoch
    2019 Mosty

    W czerwcu 2019 r. nastąpiło otwarcie nowo budowanego wiaduktu na ulicy Drwęckiej w Ostródzie, który zastąpił jeden z trzech przejazdów kolejowo-drogowych znajdujących się w centrum miasta. Zakończenie budowy bezkolizyjnego przejazdu nad torami kolejowymi pozwoliło na bezpieczne oraz szybkie połączenie północnej i południowej części Ostródy. Zastosowanie materacy z keramzytu w konstrukcji z gruntu zbrojonego.

  • Music information retrieval—The impact of technology, crowdsourcing, big data, and the cloud in art.
    • Bożena Kostek
    2019 Pełny tekst Journal of the Acoustical Society of America

    The exponential growth of computer processing power, cloud data storage, and crowdsourcing model of gathering data bring new possibilities to music information retrieval (mir) field. Mir is no longer music content retrieval only; the area also comprises the discovery of expressing feelings and emotions contained in music, incorporating other than hearing modalities for helping this issue, users’ profiling, merging music with social media and qualitative recommendations in music services. Moreover, 5g telecommunications networks, characterized by “near-instant and everything in the vicinity talks with one another,” with exponentially faster download and upload speeds, may change the existing models and create a new age of interconnectedness. This paper aims at showing some of the already highly exploited technologies and crowdsourcing models applied to music processing. Several studies are discussed in details, such as, e.g., deep learning applied to music, a way to generate an expanded training sets using 2-d data such spectrograms, mel-cepstrograms, chromagrams, and waveform-based representations of the signal instead of feature vectors in machine learning, allowing to retain all nuances related musical articulation in the signal. Also, a discussion is to be outlined, expanding the issue of the impact of these new technologies on the artistic and aesthetic values of music.

  • Music signal equalization in a changing environment
    • Piotr Hoffmann
    2019

    The paper presents the concept of an automatic system for music signal correction, considering room frequency response and music genre being played. The proposed algorithm, based on the room frequency response, compensates acoustic conditions surrounding the sound source. Additionally, the compensation process considers the signal content by recognizing music genre. As part of the described research, a series of subjective tests was presented to assess the effectiveness of the proposed algorithm depending on the music genre and acoustic conditions. The subjective tests described were carried out in accordance with the Mushra and AB methodology. In total, over 80 people took part in both tests and the results obtained from them

  • Mutual Attraction: Siemens Activities in Italy 1855-1968
    • Luciano Segreto
    2019

    The chapter deals with Siemens investments in Italy between 1855 and 1968. The contribution shows how the two war influenced the strategies of the company

  • Mutually polarizable QM/MM model with in situ optimized localized basis functions
    • Jacek Dziedzic
    • Teresa Head-Gordon
    • Martin Head-Gordon
    • Chris-Kriton Skylaris
    2019 Pełny tekst JOURNAL OF CHEMICAL PHYSICS

    We extend our recently developed quantum-mechanical/molecular mechanics (QM/MM) approach [Dziedzic et al., J. Chem. Phys. 145, 124106 (2016)] to enable in situ optimization of the localized orbitals. The quantum subsystem is described with ONETEP linear-scaling density functional theory and the classical subsystem – with the AMOEBA polarizable force field. The two subsystems interact via multipolar electrostatics and are fully mutually polarizable. A total energy minimization scheme is employed for the Hamiltonian of the coupled QM/MM system. We demonstrate that, compared to simpler models using fixed basis sets, the additional flexibility offered by in situ optimized basis functions improves the accuracy of the QM/MM interface, but also poses new challenges, making the QM subsystem more prone to overpolarization and unphysical charge transfer due to increased charge penetration. We show how these issues can be efficiently solved by replacing the classical repulsive van der Waals term for QM/MM interactions with an interaction of the electronic density with a fixed, repul- sive MM potential that mimics Pauli repulsion, together with a modest increase in the damping of QM/MM polarization. We validate our method, with particular attention paid to the hydrogen bond, in tests on water-ion pairs, the water dimer, first solvation shells of neutral and charged species, and solute-solvent interaction energies. As a proof of principle, we determine suitable repulsive potential parameters for water, K+, and Cl−. The mechanisms we employed to counteract the unphysical overpolarization of the QM subsystem are demonstrated to be adequate, and our approach is robust. We find that the inclusion of explicit polarization in the MM part of QM/MM improves agreement with fully QM calculations. Our model permits the use of minimal size QM regions and, remarkably, yields good energetics across the well-balanced QM/MM interface.

  • Nadmierne osiadania nawierzchni drogowej w ujęciu geotechnicznym – przyczyny, monitoring, możliwe metody naprawy
    • Grzegorz Horodecki
    2019 Magazyn Autostrady

    Nadmierne osiadania nawierzchni stanowią „wieczny” problem użytkowników dróg. Z odkształceniami nawierzchni łączy się obniżenie komfortu i bezpieczeństwa jazdy (BRD). Jedną z podstawowych przyczyn takiego zjawiska jest zachowanie się podłoża gruntowego. Najczęściej dotyczy to zjawiska osiadania podłoża gruntowego, stanowiącego efekt ściśliwości gruntów w wyniku przyłożenia obciążenia i jest przekroczeniem stanów granicznych użytkowalności (SGU). W rzadszych przypadkach odkształcenia wiążą się z przekroczeniem stanu granicznego nośności (SGN).

  • Nałęczów tonie w gęstwinie
    • Krzysztof Wróblewski
    • Jan Buczkowski
    2019

    Budynki, ulice, wzniesienia i jary Nałęczowa zanurzone są w gęstwienie drzew, które o każdej porze roku otulają i szczelnie zamykają miasto. Trzeba zapomnieć miejsce kilkuletniego pobytu, by ujrzeć je na nowo. Wówczas długi, wąski korytarz szkoły plastycznej i jego rozgałęzienia naturalnie łączą się z tkanką okolicy. Po latach widzi się tę przestrzeń jako wąską szczelinę albo rodzaj ucha igielnego, przez które trzeba było przejść by realizować marzenia o malarstwie.

  • Nanoconfined Ionic Liquids. Properties and analytical applications
    • Łukasz Marcinkowski
    • Adam Kloskowski
    • Jacek Namieśnik
    2019

    The synergistic combination of ionic liquids (ILs) and solid‐like matrices involves a powerful coupling towards the development of new sustainable analytical methodologies. Here we survey the literature regarding such ionic liquid‐based hybrid materials, including a database on relevant physicochemical properties of ionic liquids confined in a solid network. Furthermore, this chapter presents the strategies implemented to combine efficiently the obtained materials with analytical techniques, like microextraction techniques and biosensors. Overall, this work allows identification of the current inefficiencies, challenges, and opportunities of this convenient, yet underexploited, analytical approach.

  • Nanocrystalline Polymer Impregnated [Fe(pz)Pt(CN)4] Thin Films Prepared by Matrix-Assisted Pulsed Laser Evaporation
    • Sawczak Mirosław
    • Rafał Jendrzejewski
    • Dominik Maskowicz
    • Garcia Yann
    • Astha C. Gosh
    • Maria Gazda
    • Jakub Czechowski
    • Gerard Śliwiński
    2019 EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

    In this work, the fabrication of [Fe(pz)Pt(CN)4] (pz = pyrazine) thin films by means of matrix-assisted pulsed laser evaporation (MAPLE) was investigated. As starting material, a cryogenically cooled suspension of anocrystalline [Fe(pz)Pt- (CN)4] (0.35wt.-%) in a mixture of 1,1-dichloroethane and polyethylene glycol (PEG) was used. Films of a thickness up to 150–200 nm were deposited on Si substrates by laser ablation at λ = 1064 nm of the cryogenically cooled material. PEG impregnated films exhibit a cooperative first-order hysteretic spin crossover behavior around 155 K as detected by Raman spectroscopy. Most interestingly, deposition of a crystalline material was achieved through MAPLE deposition

  • Narracja jako sposób wyjaśniania organizacyjnej rzeczywistości oraz metoda wywierania wpływu
    • Paweł Ziemiański
    2019 Pełny tekst e-mentor

    Niniejszy artykuł ma na celu analizę roli i znaczenia narracji w funkcjonowaniu członków organizacji. W wyniku przeglądu literatury podjęto również próbę przeanalizowania mechanizmów decydujących o tym, że odpowiednio wykorzystane i skonstruowane narracje mogą służyć jako narzędzie pozwalające wywierać wpływ. Następnie na podstawie tej analizy zaproponowano wskazówki dotyczące tworzenia i przedstawiania narracji czy historii organizacyjnej (dla celów artykułu pojęcia te używane będą zamiennie) w sposób zwiększający prawdopodobieństwo skutecznego wywarcia wpływu na odbiorców. W artykule przyjęto podejście oparte na dowodach (evidence based approach), które wiąże się z przekonaniem, że wiedzę teoretyczną i wyniki badań empirycznych można wykorzystać jako podstawę praktycznych działań.

  • Nasada kominowa sposobem intensyfikacji wydajności wentylacji grawitacyjnej w budynkach mieszkalnych
    • Romana Antczak-Jarząbska
    • Maciej Niedostatkiewicz
    2019 Pełny tekst ACTA SCIENTIARUM POLONORUM. SERIA: ARCHITECTURA

    W Polsce wentylacja grawitacyjna jest najbardziej popularną metodą przewietrzania pomieszczeń, w tym lokali w budynkach mieszkalnych. Ten rodzaj wentylacji działa pod wpływem sił natury w wyniku różnicy ciśnień między powietrzem zewnętrznym a panującym wewnątrz obiektu, w następstwie czego wentylacje grawitacyjną trudno jest kontrolować oraz przewidywać poprawność jej funkcjonowania. Wentylacja grawitacyjna działa najlepiej zimą, gdy jest duża różnica temperatury oraz w wietrzne dni, gdy prędkość wiatru przekracza wartość 3 m·s–1. Najgorszy pod względem wydajności wentylacji grawitacyjnej jest okres przejściowy wiosenno-jesienny. W celu poprawy skuteczności pracy wydajności wentylacji stosuje się między innymi nasady kominowe, które mają za zadanie poprawić efekt kominowy określany w języku potocznym jako ciąg kominowy. Wydajność wentylacji określa zapotrzebowanie na powietrze wentylacyjne w pomieszczeniach. Wydajność wentylacji naturalnej (ACH) jest wyznaczana na podstawie zależności, w której niezbędne jest oszacowanie ilości powietrza wychodzącego z układu wentylacyjnego w stosunku do kubatury pomieszczenia wentylowanego. W artykule przedstawiono wpływ nasady kominowej na wydajność wentylacji grawitacyjnej poprzez wyznaczone wartości ACH. W pracy wykorzystano wyniki z badań poligonowych przeprowadzonych w istniejącym budynku.

  • NETWORKS, STAKEHOLDERS AND ENTREPRENEURIAL ECOSYSYSTEMS IN CURRENT POLISH ECONOMYGUT
    • Beata Detyna
    • Adam Gardocki
    • Stanisław Kaczyński
    • Mariusz Kaszubowski
    • Urszula Kobylińska
    • Agnieszka Mroczek-Czetwertyńska
    • Łukasz Siemieniuk
    2019 Pełny tekst

    This book is dedicated to widely understood entrepreneurship and financial system in different polish ecosystems. In particular, there is described influence of supporting entrepreneurship to investment development in Walbrzych agglomerations communes with the results of questionnaires for varied groups of inhabitants, entrepreneurs and territorial self-governments. There is also presented analysis of relations within academic support of entrepreneurship ecosystem, based on interview outcomes. Additionally there are presented, research of academic business incubators impact on infrastructure level of centers supporting development and general overview how nowadays entrepreneurship of Poles has changed. Last part of the book is an attempt to explain the potential influence of new financing system for public healthcare providers including conclusions and recommendations after first periods of its functioning.

  • New achievements in the field of extraction of trace analytes from samples characterized by complex composition of the matrix
    • Katarzyna Owczarek
    • Natalia Jatkowska
    • Justyna Płotka-Wasylka
    • Jacek Namieśnik
    2019

    Without any doubt, the monitoring of compounds present in samples at trace or ultra-trace level usually requires a preliminary step of isolation and/or enrichment of analytes due to the fact that majority of analytical techniques are not sensitive enough for direct determination of trace compounds. On the other hand, sample preparation is considered as crucial part of whole analytical procedures, in particular in samples characterized by complex composition of the matrices. Several new miniaturized extraction techniques have been introduced and extensively applied to different type of samples. Here you can highlight both, solid phase microextraction (SPME) and liquid phase microextraction (LPME). Based on the recently published literature data, this review provides an update of the most important features and application of LPME and SPME techniques. Comparisons of these techniques have been made. Discussions on the present limitations as well as expected future trends of the green techniques of sample preparation for the improvement of the analytical determinations were made. Moreover, special attention was paid on application of different types of microextraction procedures, used in the different fields of analytical chemistry.

  • New applications of sound and vision engineering
    • Andrzej Czyżewski
    2019

    Multimedia, Sound & Vision Engineering are relatively new fields within the area of science and technology, but teaching and research in this area has been carried out at Gdansk University of Technology (Gdansk, Poland) for nearly 5 decades. Current project carried-out in the Multimedia Systems Department are in the scope of the paper.

  • NEW CONCEPT OF HYBRID PROPULSION WITH HYDROSTATIC GEAR FOR INLAND WATER TRANSPORT
    • Daniel Piątek
    2019 Pełny tekst Polish Maritime Research

    The article presents the development of author’s concept of a diesel/hydraulic propulsion system for inland watercraft. Due to specific nature of vessel navigation on rivers, classical propulsion systems with shaft lines can be effectively replaced by systems with hydraulic power transmission. A solution is also presented of a hybrid design with extra electric port having the form of a pumping system driven from a battery of accumulators. Strong and weak points of the proposed solution are discussed and its energy effeciency is assessed.

  • NEW DESIGNS OF CENTRIFUGAL MAGNETIC FLUID SEALS FOR ROTATING SHAFTS IN MARINE TECHNOLOGY
    • Leszek Matuszewski
    2019 Pełny tekst Polish Maritime Research

    The centrifugal magnetic fluid seals have important advantage over the conventional centrifugal seals. They maintain very good sealing capacity at static, medium and high speeds of shaft rotation, with the increased seal lifetime, and minimum torque and static friction. These seals are particularly useful in cases when the angular shaft velocity varies and sometimes decreases to nearly or exactly zero, such as in flywheel applications, ship propeller main shafts, etc. Unique properties of the magnetic fluid give rare opportunities for application in marine design, where perfect sealing together with reliable lubrication are required. The paper presents a typical design and operation principle of a centrifugal magnetic fluid shaft seal, along with new design solutions. Not only in ocean technology and underwater robotics. Some cases of application of centrifugal magnetic fluid seals in modern sealing technology are included.

  • New generation of the satellite hydraulic pumps
    • Leszek Osiecki
    2019 Pełny tekst Journal of Mechanical and Energy Engineering

    Hydraulic satellite machines are known and produced in many versions, recognizable by the number of humps on their inner rotor and external gear, and therefore by the number of cooperating gears (satellites). All known shapes were however designed on the base of preliminary assumption that rotor’s and external gear’s pitch lines are formed by merging arcs, tangent to each other in the. This assumption makes calculations easier, but the curvature radius of the pitch lines changes instantly in their merging points. Tests made in the Department of Hydraulics and Pneumatics of the Gdańsk University of Technology proved that satellite motors may work also as a pump. All known shapes were however designed for motor work - mainly for low-speed, high-torque motors. Sudden changes of the pitch line’s curvature strongly affect velocity and acceleration of pump’s moving parts and forces between them. Because of that, in the pump mode fast wear of teeth in the points of small curvature radius is visible. The obvious effect is reduced durability and high noise emission. To eliminate all those problems the new mechanism, designed for the pump is necessary. The author worked out the new method of calculating satellite mechanism’s shape. Instead of merged arcs this method allows to form pitch line as a smooth shape with constantly variable curvature (no rapid changes in any point). Such a mechanism with two-humped rotor, four-humped external gear and six satellites was designed with the use of the new method. Curvature radii of all cooperating elements are relatively high. The proposed shape reduces rapid changes of velocity and forces between pump’s elements. It should result in more durable hydraulic satellite pump.

  • New kagome prototype materials: discovery of KV3Sb5, RbV3Sb5, and CsV3Sb5
    • Brenden R. Ortiz
    • Lídia C. Gomes
    • Jennifer R. Morey
    • Michał Winiarski
    • Mitchell Bordelon
    • John S. Mangum
    • Iain W. H. Oswald
    • Jose A. Rodriguez-Rivera
    • James R. Neilson
    • Stephen D. Wilson
    • Elif Ertekin
    • Tyrel McQueen
    • Eric S. Toberer
    2019 Pełny tekst Physical Review Materials

    In this work, we present our discovery and characterization of a new kagome prototype structure, KV3Sb5. We also present the discovery of the isostructural compounds RbV3Sb5 and CsV3Sb5. All materials exhibit a structurally perfect two-dimensional kagome net of vanadium. Density-functional theory calculations indicate that the materials are metallic, with the Fermi level in close proximity to several Dirac points. Powder and single-crystal syntheses are presented, with postsynthetic treatments shown to deintercalate potassium from single crystals of KV3Sb5. Considering the proximity to Dirac points, deintercalation provides a convenient means to tune the Fermi level. Magnetization measurements indicate that KV3Sb5 exhibits behavior consistent with a the Curie-Weiss model at high temperatures, although the effective moment is low (0.22μB per vanadium ion). An anomaly is observed in both magnetization and heat capacity measurements at 80 K, below which the moment is largely quenched. Elastic neutron scattering measurements find no obvious evidence of long-range or short-range magnetic ordering below 80 K. The possibility of an orbital-ordering event is considered. Single-crystal resistivity measurements show the effect of deintercalation on the electron transport and allow estimation of the Kadowaki-Woods ratio in KV3Sb5. We find that A/γ2∼61μOhm cm mol2FUK2J−2, suggesting that correlated electron transport may be possible. KV3Sb5 and its cogeners RbV3Sb5 and CsV3Sb5 represent a new family of kagome metals, and our results demonstrate that they deserve further study as potential model systems.

  • New Method of Non-Linear Electrochemical Impedance Spectroscopy with an Amplitude-Modulated Perturbation Signal
    • Paweł Ślepski
    • Michał Szociński
    • Joanna Majcherczak
    • Husnu Gerengi
    • Kazimierz Darowicki
    2019 JOURNAL OF THE ELECTROCHEMICAL SOCIETY

    The paper presents a new method of non-linear electrochemical impedance spectroscopy (NLEIS), which allows fast and nondestructive evaluation of the corrosion rate and determination of the Tafel coefficients values for a corrosion system under investigation. This method employs amplitude modulation of the ac perturbation signal. The study demonstrated that it was possible to obtain impedance characteristic as a function of the perturbation signal amplitude based only on a single measurement. The investigations were carried out on carbon steel exposed to 1M KCl solution, which is a model corrosion system with cathodic control. The values of corrosion current and Tafel coefficients values for the corrosion reaction were determined using the dependence between the charge transfer resistance and the amplitude of the perturbation signal

  • New potent STS inhibitors based on fluorinated 4-(1-phenyl-1H-[1,2,3]triazol-4-yl)-phenyl sulfamates
    • Mateusz Daśko
    • Sebastian Demkowicz
    • Janusz Rachoń
    • Karol Biernacki
    • Justyna Aszyk
    • Witold Kozak
    • Maciej Masłyk
    • Konrad Kubiński
    2019 Pełny tekst JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH

    A series of fluorinated analogs based on the frameworks of 4-(1- phenyl-1H-[1,2,3]triazol-4-yl)-phenyl sulfamates have been synthesized as steroid sulfatase (STS) inhibitors. The design of chemical structures of new potential STS inhibitors was supported by molecular docking techniques to identify potential interactions between inhibitors and amino acid residues located in the STS active site. The STS inhibitory potency was evaluated on STS isolated from human placenta. We found that compounds substituted with fluorine atom at the meta position demonstrated the highest inhibitory effects in enzymatic STS assay. The most active analog 12e – inhibited STS enzyme with the IC50 value of 36 nM.

  • New technologies and diffusion of innovative financial products: Evidence on exchange-traded funds in selected emerging and developed economies
    • Ewa Lechman
    • Adam Marszk
    2019 Pełny tekst JOURNAL OF MACROECONOMICS

    Exchange-traded funds (ETFs) are one of the most rapidly-expanding categories of innovative financial products that have been introduced on many financial markets, in both emerging and developed economies. Our research contributes to the present state of knowledge by examining factors, including information and communication technologies (ICTs), influencing the diffusion of ETFs. In our research, we consider also the impact of other segments of the financial system, such as the banking sector, and changes in the real side of the economy. The main aim of the paper is to provide empirical evidence on relationships between penetration of ICTs and diffusion of ETFs. Using a sample of 32 emerging and developed economies; we analyze all countries for which data on the turnover of ETFs on the local stock exchanges are available. The time span of our analysis is 2004–2014. The methodological framework combines innovation diffusion models, which are applied to characterize the key features of the process of diffusion of ETFs and ICT, with dynamic panel models, panel VAR models with exogenous variables and VAR models with exogenous variables (for country-specific analysis), which are used to examine the relationships between ETFs, ICTs, and other selected factors. Our major findings confirm that adoption of ICTs constitutes an important prerequisite for the diffusion of ETFs due to potential demand- and supply-side linkages. Among the other factors that potentially influence the diffusion of ETFs, we found three variables that demonstrate positive and statistically significant impacts: stock market turnover, financial development, and financial markets. Country-wise VAR models with selected exogenous variables confirm the influence of ICTs in most of the countries analyzed.

  • New Tetragonal ReGa5(M) (M = Sn, Pb, Bi) Single Crystals Grown from Delicate Electrons Changing
    • Madalynn Marshall
    • Karolina Górnicka
    • Ranuri S. Dissanayaka Mudiyanselage
    • Tomasz Klimczuk
    • Weiwei Xie
    2019 Pełny tekst Crystals

    Single crystals of the new Ga-rich phases ReGa~5(Sn), ReGa~5(Pb) and ReGa~5(Bi) were successfully obtained from the flux method. The new tetragonal phases crystallize in the space group P4/mnc (No. 128) with vertex-sharing capped Re2@Ga14 oblong chains. Vacancies were discovered on the Ga4 and Ga5 sites, which can be understood as the direct inclusion of elemental Sn, Pb and Bi into the structure. Heat capacity measurements were performed on all three compounds resulting in a small anomaly which resembles the superconductivity transition temperature from the impurity ReGa5 phase. The three compounds were not superconducting above 1.85 K. Subsequently, electronic structure calculations revealed a high density of states around the Fermi level, as well as non-bonding interactions that likely indicate the stability of these new phases.