127 results on '"Piotr Gajewski"'
Search Results
2. Selected physical and water properties of alluvial soils in the context of their susceptibility to drainage degradation
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Zbigniew Kaczmarek and Piotr Gajewski
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Earth and Planetary Sciences (miscellaneous) ,Soil Science ,Environmental Science (miscellaneous) - Published
- 2022
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3. Koncepcja sin tax jako instrument zapewniający ochronę zdrowia publicznego na przykładzie opłaty od środków spożywczych
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Piotr Gajewski
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General Medicine - Abstract
Badania opisane w niniejszym artykule zostały podjęte w związku z niedawną aktywnością polskiego ustawodawcy, który wprowadził opłatę od środków spożywczych do ustawy o zdrowiu publicznym. Opłata ta ma stanowić jedno z dodatkowych źródeł dochodu państwa i być wydatkowana na cele poprawy zdrowia publicznego. Celem niniejszych badań było zweryfikowanie hipotezy, że opłata od środków spożywczych stanowi realizację koncepcji sin tax obowiązującej w nauce prawa podatkowego. W toku badań została wykorzystana analiza krytyczna, w tym analiza lingwistyczna aktów prawnych. Ponadto wykorzystano analizę dorobku doktryny prawa finansowego dotyczącego koncepcji sin tax. Niniejsze badania doprowadziły do wniosków, że wprowadzona do polskiego porządku prawnego opłata od środków spożywczych stanowi formę sin tax oraz realizuje zarówno funkcję stymulacyjną, jak i alokacyjną prawa podatkowego.
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- 2022
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4. MODELOWANIE WIELOZAKRESOWEJ SIECI TAKTYCZNEJ Z DYNAMICZNYM ZARZĄDZANIEM WIDMEM
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Piotr Gajewski
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General Earth and Planetary Sciences ,General Environmental Science - Published
- 2022
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5. Thiol–ene ionogels based on polymerizable imidazolium ionic liquids
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Piotr Gajewski, Mariola Robakowska, Andrzej Skrzypczak, Agnieszka Marcinkowska, Adam Voelkel, Katarzyna Szcześniak, Aneta Lewandowska, and Zbigniew Fojud
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Polymers and Plastics ,Organic Chemistry ,Bioengineering ,Biochemistry - Abstract
In this work, we report the synthesis of polymerizable ionic liquids (PILs) and the synthesis of ionogels by thiol–ene photopolymerization.
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- 2022
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6. Selected properties of soils located within the depression cone of a planned excavation of the Drzewce open cast pit (central Poland)
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Piotr Gajewski and Zbigniew Kaczmarek
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Earth and Planetary Sciences (miscellaneous) ,Soil Science ,Environmental Science (miscellaneous) - Published
- 2021
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7. DZIAŁALNOŚć GOSPODARCZA W ROZUMIENIU USTAWY O PODATKU OD TOWARÓW I USŁUG ORAZ USTAWY O PODATKU DOCHODOWYM OD OSÓB FIZYCZNYCH
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Piotr Gajewski
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General Medicine - Abstract
Celem autora było przedstawienie zrealizowania zasady autonomii prawa podatkowego w stosunku do definicji działalności gospodarczej, która stanowi prawne odzwierciedlenie zjawiska ekonomicznego. Autor przedstawił definicję działalności gospodarczej określoną w przepisach ustaw podatkowych i porównał pod względem prawnym wyżej wymienione definicje z definicją określoną na podstawie ustawy z 6 marca 2018 r. – Prawo przedsiębiorców (Dz. U. z 2019 r. poz. 1292 ze zm.). Autor analizował powiązania pomiędzy definicjami działalności gospodarczej a realiami obrotu gospodarczego i przedstawił błędy legislacyjne zawarte w definicjach działalności gospodarczej zawarte w ustawach podatkowych. Dokonano analizy w zakresie możliwości zniwelowania obowiązków podatkowych u osób prowadzących działalność nieewidencjonowaną w rozumieniu ustawy – Prawo przedsiębiorców. W niniejszym opracowaniu w odniesieniu do badania aktów prawnych zostały wykorzystane dwie metody: dogmatycznoprawna oraz historycznoprawna. Badania zostały przeprowadzone przy użyciu krytycznej analizy orzecznictwa sądów administracyjnych oraz Trybunału Sprawiedliwości Unii Europejskiej.
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- 2021
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8. Invisible barriers: excluding accessibility from the field of interest of architecture and urban planning in Poland
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Anna Ewa Porębska, Janusz Barnaś, and Piotr Gajewski
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Engineering ,Architectural engineering ,Health (social science) ,Higher education ,business.industry ,media_common.quotation_subject ,Universal design ,Field (Bourdieu) ,General Social Sciences ,Urban planning ,General Health Professions ,Quality (business) ,Architecture ,business ,Design for All ,Built environment ,media_common - Abstract
The aim of this article is to blow the whistle on the upcoming decline in quality and accessibility of the built environment in Poland following a reform currently underway in higher education and ...
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- 2021
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9. Optimization of Ionogel Polymer Electrolytes Composition for Their Best Performance in Electric Double Layer Capacitor
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Piotr Gajewski, Agnieszka Marcinkowska, Adam Voelkel, Katarzyna Szcześniak, and Aneta Lewandowska
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Electrochemistry ,Catalysis - Published
- 2022
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10. Influence of Initiator Concentration on the Polymerization Course of Methacrylate Bone Cement
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Piotr Gajewski, Katarzyna Szcześniak, Grzegorz Przesławski, and Agnieszka Marcinkowska
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radical polymerization ,kinetics ,bone cements ,redox-initiating system ,Polymers and Plastics ,General Chemistry - Abstract
Background: The amount of oxidant (initiator) and reductant (co-initiator) and their ratio have a significant effect on the properties of polymethacrylate bone cement, such as maximum temperature (Tmax), setting time (tset) and compressive strength (σ). The increase in the initiating system concentration causes an increase in the number of generated radicals and a faster polymerization rate, which shortens the setting time. The influence of the redox-initiating composition on the course of polymerization (rate of polymerization and degree of double bond conversion) and the mechanical properties of bone cement will be analyzed. Methods: Bone cements were synthesized by mixing a powder phase composed of two commercially available methacrylate copolymers (Evonic) and a liquid phase containing 2-hydroxyethyl methacrylate (HEMA), methyl methacrylate (MMA), and triethylene glycol dimethacrylate (D3). As an initiating system, the benzoyl peroxide (BPO) as an oxidant (initiator) in combination with a reducing agent (co-initiator), N,N-dimethylaniline (DMA), was used. Samples were prepared with various amounts of peroxide BPO (0.05%, 0.1%, 0.2%, 0.3%, 0.5% and 0.7% by weight) with a constant amount of reducing agent DMA (0.5 wt.%), and various amounts of DMA (0.25%, 0.35% and 0.5% by weight) with a constant amount of BPO (0.3 wt.%). The polymerization kinetics were studied by differential scanning calorimetry (DSC). Doughing time and compressive strength tests were carried out according to the requirements of the ISO 5833:2002 standard. Results: The increase in polymerization rate was due to the increase in the amount of BPO. In addition, the curing time was shortened, as well as the time needed to achieve the maximum polymerization rate. The final conversion of the double bonds in the studied compositions was in the range 74–100%, and the highest value of this parameter was obtained by the system with 0.3 wt.% of BPO. The doughing times for each BPO concentration were in the range of 90–140 s. The best mechanical properties were obtained for the cement following the initiating system concentrations: 0.3 wt.% of BPO and 0.5 wt.% of DMA. Nevertheless, all tested cements met the requirements of the ISO 5833:2002 standard. Conclusions: Based on the conducted polymerization kinetic studies, the best reaction conditions are provided by an initiating system containing 0.3 wt.% of BPO oxidant (initiator) and 0.5 wt.% of DMA reductant (co-initiator). A decrease in the DMA amount caused a decrease in the polymerization rate and the amount of heat released during the reaction. The change in BPO and DMA concentrations in the composition had little effect on the doughing time of the studied bone cement. The cements showed similar doughing times, ranging from 90–225 s, which is comparable to the bone cement available on the market.
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- 2022
11. COVID-19 Related Myocarditis in Adults: A Systematic Review of Case Reports
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Szymon Urban, Michał Fułek, Mikołaj Błaziak, Gracjan Iwanek, Maksym Jura, Katarzyna Fułek, Mateusz Guzik, Mateusz Garus, Piotr Gajewski, Łukasz Lewandowski, Jan Biegus, Piotr Ponikowski, Przemysław Trzeciak, Agnieszka Tycińska, and Robert Zymliński
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General Medicine - Abstract
Despite the progress of its management, COVID-19 maintains an ominous condition which constitutes a threat, especially for the susceptible population. The cardiac injury occurs in approximately 30% of COVID-19 infections and is associated with a worse prognosis. The clinical presentation of cardiac involvement can be COVID-19-related myocarditis. Our review aims to summarise current evidence about that complication. The research was registered at PROSPERO (CRD42022338397). We performed a systematic analysis using five different databases, including i.a. MEDLINE. Further, the backward snowballing technique was applied to identify additional papers. Inclusion criteria were: full-text articles in English presenting cases of COVID-19-related myocarditis diagnosed by the ESC criteria and patients over 18 years old. The myocarditis had to occur after the COVID-19 infection, not vaccination. Initially, 1588 papers were screened from the database search, and 1037 papers were revealed in the backward snowballing process. Eventually, 59 articles were included. Data about patients’ sex, age, ethnicity, COVID-19 confirmation technique and vaccination status, reported symptoms, physical condition, laboratory and radiological findings, applied treatment and patient outcome were investigated and summarised. COVID-19-related myocarditis is associated with the risk of sudden worsening of patients’ clinical status, thus, knowledge about its clinical presentation is essential for healthcare workers.
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- 2022
12. Selected Aspects of the Generation of Tax Liability in the Field of Maritime Activities of Taxable Persons
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Piotr Gajewski
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business.industry ,Field (Bourdieu) ,Liability ,Accounting ,Business ,Taxable income - Abstract
This article deals with the issue of tax liability arising when taxpayers undertake economic activity in maritime areas. The research was conducted both on the grounds of direct taxes, indirect taxes and property taxes. The article verifies the hypothesis that the current provisions of Polish tax law do not fully comply with the tax authority granted to Poland as a coastal state in its maritime areas. The research method used in this study was a critical analysis, including a linguistic analysis of the provisions of tax acts and international agreements to which the Republic of Poland is a party. In addition, the research used the analysis of views of doctrine and jurisprudence of administrative courts and tax authorities.
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- 2021
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13. Elevated plasma endothelin‐1 is related to low natriuresis, clinical signs of congestion, and poor outcome in acute heart failure
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Marco Metra, Radosław Sierpiński, Joanna Tryba, Gad Cotter, Jan Biegus, Piotr Ponikowski, Mateusz Sokolski, Ewa A. Jankowska, Piotr Gajewski, Mateusz Garus, Paweł Siwołowski, Maria Samorek, and Robert Zymliński
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medicine.medical_specialty ,medicine.drug_class ,Population ,Natriuresis ,Renal function ,030204 cardiovascular system & hematology ,Congestion ,Endothelin-1 ,Spot urine sodium ,Gastroenterology ,Urine sodium ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,Original Research Articles ,Internal medicine ,medicine ,Natriuretic peptide ,Endothelin‐1 ,Diseases of the circulatory (Cardiovascular) system ,Original Research Article ,030212 general & internal medicine ,education ,education.field_of_study ,Creatinine ,business.industry ,Furosemide ,medicine.disease ,chemistry ,RC666-701 ,Heart failure ,Cardiology and Cardiovascular Medicine ,business ,medicine.drug - Abstract
Aims Endothelin‐1 (ET‐1) is a potent vasoconstrictor, which regulates renal and vascular function. We aimed to relate plasma levels of ET‐1 with the clinical picture and outcomes in acute heart failure (AHF). Methods and results We studied 113 patients with AHF [mean age 65 ± 13 (years), median (upper and lower quartiles) N‐terminal pro‐B‐type natriuretic peptide, 5422 (2689; 8582) (pg/mL)], in whom plasma levels of ET‐1 were serially measured at admission (10.8 ± 5.2), Day 1 (9.5 ± 3.4), and Day 2 (8.9 ± 3.8) (pg/mL). The population was divided into tertiles across baseline ET‐1 levels. Patients in the highest ET‐1 tertile had predominant clinical signs of peripheral congestion; however, no difference was observed in pulmonary congestion and severity of dyspnoea. They also presented lower spot urine sodium at admission (75 ± 35 vs. 99 ± 43 vs. 108 ± 30), 6 h (84 ± 34 vs. 106 ± 43 vs. 106 ± 35), and Day 1 (75 ± 38 vs. 96 ± 36 vs. 100 ± 35) (mmol/L), when compared with the second and first tertile, respectively (all P
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- 2020
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14. Novel donor-acceptor systems bearing an isoxazol-5-one core
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Mariusz Tasior, Daniel T. Gryko, Olena Vakuliuk, and Piotr Gajewski
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Core (optical fiber) ,Crystallography ,Bearing (mechanical) ,law ,Chemistry ,Organic Chemistry ,Donor acceptor ,law.invention - Published
- 2020
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15. Improved control strategy of wind energy conversion system with PMSG during low voltage sags
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Piotr Gajewski
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Control (management) ,Environmental science ,Electrical and Electronic Engineering ,Low voltage ,Automotive engineering ,Wind energy conversion - Published
- 2020
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16. Gel Polymer Electrolytes with Mixture of Triazolium Ionic Liquids and Propylene Carbonate
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Piotr Gajewski, Katarzyna Szcześniak, Aneta Lewandowska, and Agnieszka Marcinkowska
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Biomaterials ,Polymers and Plastics ,Organic Chemistry ,Bioengineering ,triazolium ionic liquids ,gel polymer electrolytes ,thiol–ene polymerization ,Kamlet–Taft parameters - Abstract
This study is focused on the structural influence of 1,2,4-triazolium ionic liquid (IL), that is, the effect of the length of the substituent and the type of substitution (1-methyl-4-alkyl or 1-alkyl-4-methyl) used in the mixture with propylene carbonate (PC) on the properties of thiol–ene polymer ionogels and on the preparation of an ionogel with satisfactory mechanical and conductive properties. PC allows for higher conductivity but also causes electrolyte leakage from the gel. When using triazolium IL (instead of the imidazolium one), because of the stronger interactions between components of the system, the ionogels do not leak. In this study, 1,4-dialkyl-1,2,4-triazolium ILs were successfully synthesized by the alkylation of 1,2,4-triazole. Subsequently, gel polymer electrolytes were obtained by one-pot thiol–ene photopolymerization reactions of tetrafunctional thiols with different chemical structures: pentaerythritol tetra(3-mercaptopropionate) (PETMP) or pentaerythritol tetra(3-mercaptobutyrate) (PETMB) and trifunctional ene (TATT) in the presence of a mixture of 1,4-dialkyl-1,2,4-triazolium IL with PC. Measurements made by electrochemical impedance spectroscopy showed that all ionogels with TATT+PETMB as a polymer matrix presented smaller relative ionic conductivity compared to ionogels containing TATT+PETMP. The puncture resistance and elongation at puncture, measured by the puncture resistance method, were higher for ionogels with poly(TATT+PETMB) than for those with poly(TATT+PETMP). Moreover, ILs containing a methyl group in position N1 of the 1,2,4-triazole ring presented lower puncture resistance than ionogels with ILs containing a methyl group in position N4, especially for shorter alkyl chains. Additionally, the photo-differential scanning calorimetry method was employed to characterize the course of photopolymerization. The compositions and their constituents were characterized by UV and IR spectroscopy.
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- 2022
17. Performance Analysis of Public Safety Cognitive Radio MANET for Diversified Traffic
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Piotr Gajewski, Jerzy Lopatka, and ŁUBKOWSKI PIOTR
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Cognition ,Electrical and Electronic Engineering ,MANET ,dynamic spectrum management ,cognitive radio ,services ,telecommunication traffic ,computer modeling ,simulations ,Biochemistry ,Instrumentation ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry - Abstract
This paper presents properties of a mobile ad hoc network (MANET) with dynamic spectrum management (DSM) and is devoted to the concept and implementation of the new traffic engine that is used in a High-Fidelity simulator of MANET with cognitive nodes for special applications. The communication traffic generated by each node is defined according to its role in the hierarchical structure of the operational scenario, determining its priorities, permission to use particular real time and non-real time services. The service usage is a source based model, defined in the user’s profile containing its statistical properties, describing periodicity, duration and randomness of traffic generation. The overall traffic generated by the node is a combination of traffics related to specific services. Their statistical parameters are based on real exercises results. The model was defined in the Matlab environment and next verified using the MAENA simulator for complex, operational scenarios. The achieved results show that use of both central and distributed DSM provides a better performance of the MANET network with complex traffic.
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- 2022
18. Review of Soft Actuators Controlled with Electrical Stimuli: IPMC, DEAP, and MRE
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Piotr Gajewski, Jakub Bernat, Agnieszka Marcinkowska, and Jakub Kolota
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Fluid Flow and Transfer Processes ,Process Chemistry and Technology ,General Engineering ,General Materials Science ,Instrumentation ,Computer Science Applications - Abstract
Soft actuators have been developed for a variety of applications, including soft grippers, artificial muscles, wearables, tactile devices, and medical devices. In this review, we will discuss a group of chemical materials and their robotic applications in soft actuators controlled with electrical stimuli. Soft actuators provide a deformable body and allow interaction with the environment to achieve the desired actuation pattern. We will also discuss the principles of operation and functionality and focus on important real-life applications of three groups of soft actuators: ionic polymer–metal composites (IPMCs), dielectric electroactive polymers (DEAPs), and magnetorheological elastomers (MREs). This review article aims to provide researchers interested in the field of soft robotics with a guide to various state-of-the-art chemistry methods used in electrically activated soft actuators, as well as the application areas for such devices.
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- 2023
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19. Discontinuation of hydration and nutrition in vegetative or minimally conscious state: position statement of the Polish Association for Spiritual Care in Medicine 2020
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Jakub, Pawlikowski, Andrzej, Muszala, Piotr, Gajewski, Małgorzata, Krajnik, and On Behalf Of, The Board Of The Polish Association For Spiritual Care In Medicine
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Position statement ,medicine.medical_specialty ,Withholding Treatment ,business.industry ,Persistent Vegetative State ,MEDLINE ,Minimally conscious state ,medicine.disease ,Discontinuation ,Spirituality ,Internal Medicine ,medicine ,Humans ,Poland ,Spiritual care ,Psychiatry ,Association (psychology) ,business - Published
- 2021
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20. Hydrogel–Polymer Electrolyte for Electrochemical Capacitors with High Volumetric Energy and Life Span
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François Béguin and Piotr Gajewski
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musculoskeletal diseases ,Polypropylene ,Materials science ,General Chemical Engineering ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Electrochemistry ,01 natural sciences ,0104 chemical sciences ,Polyolefin ,Carboxymethyl cellulose ,Contact angle ,chemistry.chemical_compound ,General Energy ,Membrane ,chemistry ,Chemical engineering ,Pulmonary surfactant ,medicine ,Environmental Chemistry ,General Materials Science ,0210 nano-technology ,medicine.drug - Abstract
AC/AC (AC=activated carbon) electrochemical capacitors (ECs) were designed with a 1 mol L-1 lithium sulfate hydrogel- polymer electrolyte (HPE) based on carboxymethyl cellulose sodium salt (CMC). The electrochemical performance of the ECs was compared with that of cells composed of common separators such as a polyolefin membrane (Celgard 3501, polypropylene separator coated by surfactant) and a glass microfiber membrane (Whatman GF/A). The ECs with Celgard 3501 and home-made CMC-HPE demonstrated a higher volumetric energy than that with Whatman GF/A. However, after 120 h of floating at 1.5 V, the capacitance of the EC with Celgard 3501 decreased dramatically by 25 %, whereas with CMC-HPE and Whatman GF/A, the decrease was only 4 and 6 %, respectively. Post-mortem observations of the Celgard 3501 separator after floating suggested that the surfactant layer was removed, which caused a decrease of separator wettability, as confirmed by the slow evolution of the electrolyte contact angle on its surface. Hence, CMC-HPE is a very attractive option to develop aqueous-electrolyte-based ECs with an excellent life span and high volumetric energy density.
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- 2020
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21. Traffic Modelling for Mobile Ad-hoc Networks Simulation
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Piotr Lubkowski, Piotr Gajewski, and Jerzy Lopatka
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Hierarchy ,Signal processing ,Computer science ,business.industry ,media_common.quotation_subject ,Statistical parameter ,Mobile ad hoc network ,Control system ,Node (computer science) ,Quality (business) ,business ,Heterogeneous network ,media_common ,Computer network - Abstract
This paper is devoted to develop new traffic engine that can be used in High Quality simulator of MANET with cognitive nodes for special applications. This network incudes different categories of nodes, according to their roles in communication and control system hierarchy. Each category of nodes is characterized by its traffic profile, described by intensity of use of specific services. The overall traffic generated by the node is a combination of traffics related to specific services, and their statistical parameters are coming from real exercises.
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- 2021
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22. Influence of the Addition of Sialon and Aluminum Nitride Fillers on the Photocuring Process of Polymer Coatings
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Piotr Gajewski, Mariola Robakowska, Łukasz Gierz, Agnieszka Marcinkowska, Katarzyna Szcześniak, Paulina Mayer, and Aneta Lewandowska
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aluminum nitride ,sialon ,UV-curable coating ,UV-curing kinetics ,hydrophobicity ,thermal properties ,surface wettability ,Materials Chemistry ,Surfaces and Interfaces ,Surfaces, Coatings and Films - Abstract
This article presents the results of a study on polymer coatings containing poly ethoxylated bisphenol A diacrylate (Bis-AEA10) with aluminum silicon nitride oxide (Sialon) and aluminum nitride (AlN). The polymer coatings were obtained by the photopolymerization technique. Investigations were carried out to determine the effect of the AlN and Sialon content on the UV-curing kinetics, as well as on the mechanical (hardness), thermal (Tg, thermal stability), physicochemical (water contact angle), and structural properties of the polymer coatings. Polymerization rates were characterized as functions of double-bond conversion using the photo-Differential Scanning Calorymetry technique (photo-DSC). The results obtained showed that a small addition of sialon filler (3–5 wt.%) to Bis-AEA10 increases the photopolymerization rate of the varnish, while the addition of more Sialon decreases the rate of photopolymerization. However, for the systems containing AlN filler, the maximum polymerization rate was observed for samples containing 10 wt.% filler. In the case of a varnish composition containing AlN, the maximum polymerization rate is characterized by the system containing 10 wt.% of AlN. This shows that the AlN filler has a good influence on the polymerization process. In either case, the final double bond conversion was high (80%–95%). Mechanical tests have shown that introducing the filler into the polymer matrix increases its hardness. The content of Sialon and AlN in the coatings causes an increase (up to 4–5 wt.%) and a decrease (>4–5 wt.%) in the glass transition temperature. The effect of the addition of fillers on the physicochemical properties of the coating surface has also been investigated and characterized by the water contact angle method. The addition of 20 wt.% Sialon and AlN increased the contact angle of the samples by approximately 40% and 31%, respectively, resulting in coatings with hydrophobic surface properties.
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- 2022
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23. Silicone-Based Membranes as Potential Materials for Dielectric Electroactive Polymer Actuators
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Piotr Gajewski, Jakub Bernat, Agnieszka Marcinkowska, and Jakub Kolota
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Control and Optimization ,Renewable Energy, Sustainability and the Environment ,Energy Engineering and Power Technology ,Building and Construction ,Electrical and Electronic Engineering ,Engineering (miscellaneous) ,dielectric electroactive polymer ,smart material ,silicone membrane ,actuator ,Energy (miscellaneous) - Abstract
This article includes an overview of the materials and a thorough analysis of the methods that are used to produce dielectric electroactive actuator membranes. The paper also presents extensive results from our experimental studies on two types of addition silicone (Silicone Mold Start 15 and Dragon Skin 10M) that are used to manufacture actuators with different active membranes of thicknesses (165 μm and 300 μm, respectively). This study explored in depth the hardware architectures and methodologies for manufacturing the selected actuators. The displacements of the actuators were compared to their responses to two types of voltage excitation: a step response and a sinusoidal signal with an increasing frequency over time. This paper graphically presents the results that we obtained for all devices, with a particular emphasis on the resonance frequencies. When comparing membranes that had the same thickness (165 μm), it was found that the mean amplitude was higher for silicone membranes with lower values for the Young’s modulus (DS = 0.57 mm and MS = 0.73 mm). All experiments were repeated for two series of measurements and the results that were obtained in this study demonstrated the successful implementation of the actuator concepts that were made from the new types of silicone, which have not yet been used for production.
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- 2022
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24. 2021 Signal Processing Symposium (SPSympo)
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Piotr Gajewski, Konrad Jedrzejewski, and ŁUBKOWSKI PIOTR
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- 2021
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25. Interference Resistant Waveform for Cognitive Radio MANET
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R. Chęciński, Anna Kaszuba-Checinska, Jerzy Lopatka, and Piotr Gajewski
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Cognitive radio ,business.industry ,Software deployment ,Computer science ,Testbed ,Overhead (computing) ,Waveform ,Mobile ad hoc network ,business ,Interference (wave propagation) ,Dynamic spectrum management ,Computer network - Abstract
The problem of waveforms constructing for mobile ad hoc networks with cognitive radio (MANET-CR) is discussed. This is one of the main questions limiting widely use this very attractive technique, that not need deployment of expensive communication infrastructure. The paper presents the structure of CR nodes with complex management procedures, using advanced Dynamic Spectrum Management together with the concept of policy-based radio. Here, the basic policy is to avoid interference generated by other users or interfering devices. The experiments were performed in a real environment, using the elaborated testbed. The results show that the use of sensing and cognitive management mechanisms enables more efficient use of the spectrum while maintaining reasonable overhead values related to the management procedures.
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- 2020
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26. Persistent hyperlactataemia is related to high rates of in-hospital adverse events and poor outcome in acute heart failure
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Jan Biegus, Robert Zymliński, Justyna M. Sokolska, Maciej Banasiak, Paweł Siwołowski, Piotr Gajewski, Mateusz Sokolski, Piotr Ponikowski, Waldemar Banasiak, and Katarzyna Swoboda
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Male ,medicine.medical_specialty ,Critical Illness ,Population ,030204 cardiovascular system & hematology ,03 medical and health sciences ,0302 clinical medicine ,Internal medicine ,Intensive care ,medicine ,Humans ,Hyperlactatemia ,Lactic Acid ,Adverse effect ,education ,Prospective cohort study ,Aged ,Aged, 80 and over ,Heart Failure ,education.field_of_study ,Ejection fraction ,business.industry ,Hazard ratio ,Length of Stay ,Middle Aged ,Prognosis ,medicine.disease ,Confidence interval ,Hospitalization ,Heart failure ,Cardiology ,Female ,Cardiology and Cardiovascular Medicine ,business ,Biomarkers - Abstract
Background: Although lactate is a well-established marker in intensive care, our understanding of its utility in acute heart failure (AHF) is modest and based on studies with a single measurement of this marker. Aims: We aimed to investigate whether persistent elevation of lactate during hospitalisation is related to a higher risk of ad- verse events. Methods: We conducted a prospective study to assess AHF patients hospitalised in one cardiac centre. The diagnosis of persistent hyperlactataemia was based on two measurements of the marker (on admission and at 24 h of hospitalisation) and it was defined as lactate elevation (≥ 2 mmol/L) at both time points. Results: The population consisted of 222 patients at a mean age of 70 ± 13 years. Mean ejection fraction and creatinine level on admission were 37% ± 16% and 1.36 ± 0.51 mg/dL, respectively. The percentage of patients with elevated lactates on admission, at 24 h of hospitalisation, and persistent hyperlactataemia were 47%, 35%, and 24%, respectively. The group with persistent hyperlactataemia did not differ in most clinical and laboratory variables from the rest of the population. Patients with persistent hyperlactataemia had higher rate of adverse events during hospitalisation: worsening of heart failure (22.6% vs. 6.5%, p < 0.05), inotrope use (22.6% vs. 5.3%, p < 0.05), and increase of N-terminal pro–B-type natriuretic peptide at 48 h of hospitalisation (30% vs. 18%, p < 0.05). Persistent hyperlactataemia was an independent predictor of one-year mortality (hazard ratio 2.5, 95% confidence interval 1.5–4.3, p < 0.001). Conclusions: Persistent hyperlactataemia within the first 24 h of hospitalisation is a predictor of a worse outcome in AHF and is related to higher rates of in-hospital adverse events and one-year mortality.
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- 2019
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27. Design, Fabrication and Analysis of Magnetorheological Soft Gripper
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Rafal Kapela, Piotr Gajewski, Paulina Superczynska, Jakub Bernat, and Agnieszka Marcinkowska
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Magnetic Fields ,Elastomers ,Robotics ,Electrical and Electronic Engineering ,Biochemistry ,Instrumentation ,magnetorheological elastomers ,MRE ,soft gripper ,Atomic and Molecular Physics, and Optics ,Analytical Chemistry - Abstract
The magnetorheological elastomer is promising material for applications in soft robotics. Its properties like reactive to external magnetic field and softness allow to construct an attractive devices. This work presents a construction of soft gripper assembled with magnetorheological elastomers. The work describes the detailed molding process of magnetorheological elastomers. Further, the electromechanical properties of magnetorheological elastomers are shown using a simple beam. Finally, the soft gripper is constructed and analyzed with the series of experiments.
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- 2022
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28. Polityka ustawodawcy w zakresie podejmowania, wykonywania i zakończenia działalności gospodarczej
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Piotr Gajewski
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Entrepreneurship ,Constitution ,Field (Bourdieu) ,Political science ,media_common.quotation_subject ,Economic law ,Business activities ,Relation (history of concept) ,Law and economics ,media_common - Abstract
In the article, the author defined what objectives and values the Polish law-giver is guided by in the field of regulations regarding public economic law. He referred to both the Freedom of Business Activity Act and the Entrepreneurship Law Act, as well as to the relation of the economic law with EU law and the Polish Constitution. This study also considers the possibility of ensuring equality for economic entities and freedom of economic activity.
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- 2018
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29. Early Hemodynamic Changes following Surgical Ablation of the Right Greater Splanchnic Nerve for the Treatment of Heart Failure with Preserved Ejection Fraction
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Piotr Gajewski, Marat Fudim, Veraprapas Kittipibul, Zoar J. Engelman, Jan Biegus, Robert Zymliński, and Piotr Ponikowski
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General Medicine - Abstract
Background: Permanent ablation of the right greater splanchnic nerve (GSN) has previously been demonstrated to improve quality of life and functional outcomes, as well as reduce abnormally high intracardiac filling pressures, in patients with heart failure with preserved ejection fraction (HFpEF) at 1, 3 and 12 months following the procedure. We hypothesize that hemodynamic changes that ensue from surgical right GSN ablation would be apparent as early as 24 h after the medical intervention. Methods and Results: This is a prespecified analysis of a single-arm, two-center, open-label study evaluating the effects of right GSN ablation via thoracoscopic surgery in HFpEF patients with pulmonary capillary wedge pressure (PCWP) ≥15 mmHg at rest or ≥25 mmHg with supine cycle ergometry. A total of seven patients (median age 67 years, 29% female) underwent GSN removal followed by invasive right heart catheterization within 24 h. GSN ablation resulted in a significant reduction in PCWP 24 h after the procedure compared to baseline for both 20 W exercise (baseline (28.0 ± 4.3 mmHg) to 24 h (19.6 ± 6.9 mmHg); p = 0.0124) and peak exercise (baseline (25.6 ± 2.4 mmHg) to 24 h (17.4 ± 5.9 mmHg); p = 0.0025). There were no significant changes in resting or leg-up hemodynamics. Conclusions: Permanent right GSN ablation leads to a reduction in intracardiac filling pressures during exercise, apparent as early as 24 h following the procedure.
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- 2022
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30. TRANSPORT TOWARÓW W MIEŚCIE Z WYKORZYSTANIEM 6 ZAŁOŻEŃ EKONOMII WSPÓŁDZIELENIA
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Poznań Katedra Logistyki Międzynarodowej Uniwersytet Ekonomiczny and Piotr Gajewski
- Published
- 2018
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31. The Influence of Monomer Structure on the Properties of Ionogels Obtained by Thiol–Ene Photopolymerization
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Piotr Gajewski, Katarzyna Szcześniak, Agnieszka Marcinkowska, and Aneta Lewandowska
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Materials science ,Polymers and Plastics ,Science ,General. Including alchemy ,Bioengineering ,Pentaerythritol ,Article ,Biomaterials ,chemistry.chemical_compound ,QD1-65 ,Differential scanning calorimetry ,Polymer chemistry ,Trimethylolpropane ,QD1-999 ,photopolymerization kinetics ,QD146-197 ,chemistry.chemical_classification ,Organic Chemistry ,thiol–ene polymerization ,Polymer ,Kamlet–Taft parameters ,gel polymer electrolytes ,Chemistry ,Monomer ,Photopolymer ,chemistry ,Polymerization ,ionogels ,Ionic liquid ,Inorganic chemistry - Abstract
The influence of ene and thiol monomer structure on the mechanical and electrochemical properties of thiol–ene polymeric ionogels were investigated. Ionogels were obtained in situ by thiol–ene photopolymerization of 1,3,5-triallyl-1,3,5-triazine-2,4,6(1H,3H,5H)-trione (TATT), 2,4,6-triallyloxy-1,3,5-triazine (TAT), diallyl phthalate (DAP), and glyoxal bis(diallyl acetal) (GBDA) used as enes and trimethylolpropane tris(3-mercaptopropionate) (TMPTP), pentaerythritol tetrakis(3-mercaptopropionate) (PETMP), and pentaerythritol tetrakis(3-mercaptobutyrate) (PETMB) used as thiols in 70 wt.% of ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMImNTf2). The mechanical strength of ionogels was studied by puncture resistance and ionic conductivity by electrochemical impedance spectroscopy. The course of photopolymerization by photo-DSC method (differential scanning calorimetry) as well as characterization of compositions and its components (by IR and UV spectroscopy-Kamlet–Taft parameters) were also studied. The resulting ionogels were opaque, with phase separation, which resulted from the dispersion mechanism of polymerization. The mechanical and conductive properties of the obtained materials were found to be largely dependent on the monomer structure. Ionogels based on triazine monomers TAT and TATT were characterized by higher mechanical strength, while those based on aliphatic GBDA had the highest conductivity. These parameters are strongly related to the structure of the polymer matrix, which is in the form of connected spheres. The conductivity of ionogels was high, in the range of 3.5–5.1 mS∙cm−1.
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- 2021
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32. Discontinuation of hydration and nutrition in vegetative or minimally conscious state: no straightforward answer. Authors’ reply
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Jakub Pawlikowski, Piotr Gajewski, Małgorzata Krajnik, and Andrzej Muszala
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medicine.medical_specialty ,2019-20 coronavirus outbreak ,Withholding Treatment ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Persistent Vegetative State ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,MEDLINE ,Minimally conscious state ,medicine.disease ,Discontinuation ,Internal Medicine ,medicine ,Humans ,Spirituality ,Poland ,Intensive care medicine ,business - Published
- 2021
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33. Disinfectant Susceptibility of Biofilm Formed by
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Krzysztof, Skowron, Ewa, Wałecka-Zacharska, Katarzyna, Grudlewska, Piotr, Gajewski, Natalia, Wiktorczyk, Magdalena, Wietlicka-Piszcz, Andżelika, Dudek, Karolina Jadwiga, Skowron, and Eugenia, Gospodarek-Komkowska
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L. monocytogenes ,biofilm formation ,biochemical phenomena, metabolism, and nutrition ,biofilm resistance ,disinfectants ,stainless steel ,Article ,environmental conditions - Abstract
Listeria monocytogenes is a one of the most important food-borne pathogens. Its ability to form biofilm contributes to increased resistance to disinfectants and inefficient disinfection, posing a serious threat for the food industry, and in the end the consumer. The aim of this study was the comparison of the biofilm formation ability of L. monocytogenes strains on stainless steel, under different environmental conditions (temperature, pH, NaCl concentration, nutrients availability), and the assessment of biofilm susceptibility to disinfectants. The bactericidal activity of four disinfectants in two concentrations (100% and 50% of working solution) against biofilm was conducted on four clinical strains, four strains isolated from food and one reference strain ATCC 19111. It was found that biofilm susceptibility to disinfectants was influenced by environmental conditions. Biofilm susceptibility correlated with the decrease of temperature, pH, nutrients availability and salinity of the environment. The least sensitive to disinfectants was biofilm produced at pH = 4 (the bacterial number ranged from 0.25 log CFU × cm−2 to 1.72 log CFU × cm−2) whereas the most sensitive was biofilm produced at pH = 9 (5.16 log CFU × cm−2 to 7.84 log CFU × cm−2). Quatosept was the most effective disinfectant, regardless of the conditions. In conclusion, biofilm susceptibility to disinfectants is strain-dependent and is affected by environmental conditions.
- Published
- 2019
34. Long-chain α–ω diols from renewable fatty acids via tandem olefin metathesis–ester hydrogenation
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Mike Schmitkamp, Piotr Gajewski, Angela Gonzalez-de-Castro, Mae Joanne B. Aguila, Laurent Lefort, Elena Cosimi, and Johannes G. de Vries
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inorganic chemicals ,chemistry.chemical_classification ,Tandem ,010405 organic chemistry ,Ligand ,organic chemicals ,Diol ,Noyori asymmetric hydrogenation ,Fatty acid ,010402 general chemistry ,Metathesis ,01 natural sciences ,Pollution ,0104 chemical sciences ,Catalysis ,chemistry.chemical_compound ,chemistry ,Environmental Chemistry ,Organic chemistry ,heterocyclic compounds ,Selectivity - Abstract
Long chain α–ω diols were readily accessed from renewable fatty acid methyl esters following an orthogonal tandem self-metathesis–ester hydrogenation protocol. By adding a base and a bidentate ligand, the metathesis catalysts were transformed in situ into efficient ester hydrogenation catalysts. The selectivity of the hydrogenation reaction was tuned towards the exclusive formation of either the unsaturated or the saturated diol by modifying the ligand/catalyst ratio. An orthogonal tandem cross-metathesis–ester hydrogenation reaction was also applied for the synthesis of a fragrance compound.
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- 2017
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35. Advanced control of direct-driven PMSG generator in wind turbine system
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Krzysztof Pieńkowski and Piotr Gajewski
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Generator (computer programming) ,Computer science ,020209 energy ,General Engineering ,030206 dentistry ,02 engineering and technology ,Turbine ,simulation studies ,Automotive engineering ,MPPT control ,wind turbine ,03 medical and health sciences ,0302 clinical medicine ,Pitch control ,pitch control ,PMSG generator ,0202 electrical engineering, electronic engineering, information engineering ,lcsh:Electrical engineering. Electronics. Nuclear engineering ,lcsh:TK1-9971 - Abstract
The paper presents the advanced control system of the wind energy conversion with a variable speed wind turbine. The considered system consists of a wind turbine with the permanent magnet synchronous generator (PMSG), machine side converter (MSC), grid side converter (GSC) and control circuits. The mathematical models of a wind turbine system, the PMSG generator and converters have been described. The control algorithms of the converter systems based on the methods of vector control have been applied. In the advanced control system of the machine side converter the optimal MPPT control method has been used. Additionally the pitch control scheme is included in order to achieve the limitation of maximum power and to prevent mechanical damage of the wind turbine. In the control system of the grid side converter the control of active and reactive power has been applied with the application of Voltage Oriented Control (VOC). The performance of the considered wind energy system has been studied by digital simulation. The results of simulation studies confirmed the good effectiveness of the considered wind turbine system and very good performance of the proposed methods of vector control and control systems.
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- 2016
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36. Impaired hepato-renal function defined by the MELD XI score as prognosticator in acute heart failure
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Waldemar Banasiak, Paweł Siwołowski, Piotr Ponikowski, Robert Zymliński, Sylwia Nawrocka-Millward, Piotr Gajewski, Ewa A. Jankowska, Elżbieta Poniewierka, Jan Biegus, and Mateusz Sokolski
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medicine.medical_specialty ,Creatinine ,business.industry ,Bilirubin ,Hazard ratio ,Renal function ,030204 cardiovascular system & hematology ,medicine.disease ,Confidence interval ,Surgery ,body regions ,03 medical and health sciences ,chemistry.chemical_compound ,0302 clinical medicine ,chemistry ,Heart failure ,Internal medicine ,medicine ,Population study ,030212 general & internal medicine ,Liver function ,Cardiology and Cardiovascular Medicine ,business - Abstract
Aim Multi-organ dysfunction often complicates the natural course of acute heart failure (AHF) and identifies patients with poor prognosis. The MELD score (Model of End-Stage Liver Dysfunction) combines data reflecting liver and kidney function, which makes it a potentially useful tool for the assessment of patients with AHF. To assess the prognostic utility of the MELD score in patients with AHF. Methods and results The MELD score was calculated on admission and during hospital stay (days 2–3) using a formula that does not take into account the international normalized ratio (MELD XI). The study population consisted of 203 AHF patients (mean age 65 ± 12 years, 76% male). The mean MELD XI score was −14.8 ± 4.5 points on admission and 13.9 ± 4.3 points during hospitalization. Contributors of elevated MELD XI score at baseline and during hospital stay were isolated increase in creatinine in 22–25%, isolated increase in bilirubin in 17–19%, and abnormal values of both in 40–46% of patients. During 1-year follow-up, 67 (33%) patients died. After adjustment for well-established prognosticators, MELD XI score at baseline and during hospital stay were significant predictors of poor outcome [hazard ratio (95% confidence interval): 1.11 (1.05–1.2) and 1.14 (1.09–1.2), respectively, P < 0.001]. An increase in the MELD XI score during hospital stay occurred in 31% of patients and was related to increased risk of death at 1 year [1.97 (1.2–3.2), P < 0.005]. Conclusions Impairment of hepato-renal function defined by the MELD XI score is common and carries unfavourable prognosis in AHF patients.
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- 2016
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37. A Mixed Ligand Approach for the Asymmetric Hydrogenation of 2-Substituted Pyridinium Salts
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Piotr Gajewski, Umberto Piarulli, Marc Renom-Carrasco, Johannes G. de Vries, Cesare Gennari, Luca Pignataro, Laurent Lefort, and Synthetic Organic Chemistry
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MONODENTATE LIGANDS ,Noyori asymmetric hydrogenation ,010402 general chemistry ,PIPERIDINES ,01 natural sciences ,Catalysis ,chemistry.chemical_compound ,Organic chemistry ,Phosphoramidite ,DERIVATIVES ,010405 organic chemistry ,Organic Chemistry ,Asymmetric hydrogenation ,Enantioselective synthesis ,asymmetric catalysis ,Iminium ,General Chemistry ,homogeneous catalysis ,hydrogenation ,pyridines ,reaction mechanisms ,Combinatorial chemistry ,QUINOLINES ,0104 chemical sciences ,HIGHLY ENANTIOSELECTIVE HYDROGENATION ,chemistry ,IRIDIUM-CATALYZED HYDROGENATION ,MULTIPLE STEREOGENIC CENTERS ,PHOSPHORAMIDITES ,COMPLEXES ,ISOQUINOLINIUM SALTS ,Pyridinium ,Phosphine - Abstract
Herein we describe a new methodology for the asymmetric hydrogenation (AH) of 2-substituted pyridinium salts. An iridium catalyst based on a mixture of a chiral monodentate phosphoramidite and an achiral phosphine was shown to hydrogenate N-benzyl-2-arylpyiridinium bromides to the corresponding N-benzyl-2-arylpiperidines with full conversion and good enantioselectivity. The mechanism of the reaction under optimized conditions was investigated via kinetic measurements and isotopic labeling experiments. Our study suggests that the hydrogenation starts with a 1,4-hydride addition and that the enantiodiscriminating step involves the reduction of an iminium intermediate.
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- 2016
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38. Control of the Hybrid Renewable Energy System with Wind Turbine, Photovoltaic Panels and Battery Energy Storage
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Piotr Gajewski, Piotr Ponikowski, and Krzysztof Pienkowski
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Control and Optimization ,converter control system ,Computer science ,Energy management ,020209 energy ,Energy Engineering and Power Technology ,02 engineering and technology ,Permanent magnet synchronous generator ,lcsh:Technology ,Turbine ,Maximum power point tracking ,Energy storage ,Automotive engineering ,wind turbine ,battery energy storage ,0202 electrical engineering, electronic engineering, information engineering ,Energy transformation ,Electrical and Electronic Engineering ,hybrid renewable energy system ,photovoltaic systems ,simulation studies ,Engineering (miscellaneous) ,lcsh:T ,Renewable Energy, Sustainability and the Environment ,020208 electrical & electronic engineering ,Photovoltaic system ,Hybrid system ,Energy (miscellaneous) - Abstract
The aim of the paper is the study of the Hybrid Renewable Energy System, which is consisted of two types of renewable energy systems (wind and sun) and is combined with storage energy system (battery). The paper presents the classification and review of architectures of Hybrid Renewable Energy Systems. The considered Hybrid Renewable Energy System was designed as a multi-converter system with gearless Wind Turbine driven Permanent Magnet Synchronous Generator and with a Photovoltaic Array and Battery Energy System. The mathematical models of individual elements of a complex Hybrid Renewable Energy System were described. In the control of both systems of Wind Turbine with Permanent Magnet Synchronous Generator and Photovoltaic array, the algorithms of Maximum Power Point Tracking have been implemented for higher efficiency of energy conversion. The energy storage in the battery has been managed by the control system of a bidirectional DC/DC converter. For the control of the Machine Side Converter and Wind Turbine with Permanent Magnet Synchronous Generator, the vector control method has been implemented. In the control system of the Grid Side Converter, the advanced method of Direct Power Control has been applied. The energy management strategies for optimal flows of electrical energy between individual systems of considered hybrid renewable energy system are developed and described. In order to determine the operation of proposed control systems, the simulation studies have been performed for different conditions of operation of individual elements of the complex hybrid system. The considered control methods and energy management strategies were tested thorough simulation studies for different wind speed variations, different sun irradiations, and different local load demands. The performed simulations are of practical importance in terms of proper operation requirements, design selection of components and energy management of Hybrid Renewable Energy Systems.
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- 2021
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39. Tactical Radio Operator’s Combat Readiness as Context Information for Dynamic Spectrum Management Within Military Mobile Ad Hoc Network
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Joanna Glowacka, Wojciech Bednarczyk, Jaroslaw Wojtun, Michał Ciołek, Piotr Gajewski, and Krzysztof Parobczak
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royalty.noble_title ,Computer science ,Combat readiness ,royalty ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Context (language use) ,Mobile ad hoc network ,Computer security ,computer.software_genre ,Spectrum management ,Dynamic spectrum management ,Radio operator ,Operator (computer programming) ,computer ,Search and rescue - Abstract
The Authors present a new approach to a method of dynamic spectrum management within military mobile ad hoc network. They propose that data concerning tactical radio operator’s combat readiness be used as context information for spectrum management. The readiness is determined based on monitored vital signs of and interaction with the tactical radio operator. If the operator’s inability to operate and protect the tactical radio is identified, actions are taken with the aim to release spectrum resources used by the tactical radio or in order to switch the tactical radio to modes used by search and rescue team.
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- 2019
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40. Use of tactical radio operator’s vital signs as context information for dynamic spectrum management within MANETs
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Michał Ciołek, Krzysztof Parobczak, Piotr Gajewski, Joanna Glowacka, and Jaroslaw Wojtun
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royalty.noble_title ,combat readiness ,lcsh:T ,Computer science ,context in-formation ,Vital signs ,royalty ,dynamic spectrum management ,Context (language use) ,Computer security ,computer.software_genre ,lcsh:Technology ,Dynamic spectrum management ,vital signs ,Radio operator ,remote radio control ,manet ,computer - Abstract
INTRODUCTION: The Authors present a new approach to a method of dynamic spectrum management for militarymobile ad hoc network. They propose that data concerning vital signs of tactical radio operators be used as contextinformation for spectrum management. If the operator’s inability to operate and protect the tactical radio is identified,actions (remote control of radio) are taken with the aim to release spectrum resources which used by the radio.Additionally, in this case remote control of radio allows switch the radio to modes used by search and rescue teams andlock the radio for unauthorized person.OBJECTIVES: The primary objective of this study was use vital signs of tactical radio operator’s as context informationfor dynamic spectrum management within MANET.METHODS: Tests for correct detection of vital signs were carried out for data generated on a Hal S3201 adult patientsimulator. Hypotheses about radio operator's vital signs were verified by means of a belief function defined in DempsterShafer theory.RESULTS: Loss vital signs by the operator allows to remote turn off his/her tactical radio while allocating more resourcesto other network users, which allow increasing data throughput.CONCLUSION: Monitoring vital signs of a tactical radio operator enables detecting combat readiness loss which resultsin inability to protect communications and can be used in spectrum management mechanisms.
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- 2020
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41. Zastosowanie śrub biowchłanialnych w porównaniu ze śrubami metalowymi w truamatologii dziecięcej
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Elzbieta Gawrych, Piotr Gajewski, Gabriela Grochowska, Ireneusz Walaszek, and Kaja Giżewska-Kacprzak
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medicine.medical_specialty ,Osteolysis ,business.industry ,Surgical removal ,medicine ,Dentistry ,Traumatology ,General Medicine ,Pain management ,medicine.disease ,business ,Operative fixation ,Screw fixation - Abstract
Introduction: Metal stabilizing implants used in pediatric fractures have to be removed to not inhibit the growth of bones. Bioabsorbable implants can save children from surgical removal of the fixating material. As there have been only a few reports regarding children, we decided to evaluate the clinical advantages of bioabsorbable screws in the treatment of selected bone fractures in pediatric traumatology.Materials and methods: The study group included 35 patients with bone fractures aged 5–17 years (mean 13.2 years) fixed with LactoSorb® bioabsorbable screws made of polymeric lactic acid and polyglycolic acid. The follow-up was compared with a matched control group of 35 children that underwent operative fixation of the same type of fractures with metal screws. Results: Clinical and radiological follow-up showed that bone unions were obtained in all cases, with no signs of osteolysis. The time of immobilization was slightly shorter in the study group (5.5 weeks) than among controls (6.2 weeks; p = 0.038). There were no differences in complications, wound infections, pain management and time of hospitalization between both groups.Conclusions: The use of bioabsorbable material in the treatment of fractures in pediatric traumatology is a safe alternative to metal stabilizing devices, with clinical benefits for young patients including no necessity of a second surgery and anesthesia.
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- 2018
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42. Clinical, respiratory, haemodynamic, and metabolic determinants of lactate in heart failure
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Piotr Ponikowski, Waldemar Banasiak, Jan Biegus, Robert Zymliński, Piotr Gajewski, and Mateusz Sokolski
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Adult ,Male ,medicine.medical_specialty ,Population ,Cardiac index ,030204 cardiovascular system & hematology ,Ventricular Function, Left ,03 medical and health sciences ,0302 clinical medicine ,Heart Rate ,Internal medicine ,Natriuretic Peptide, Brain ,medicine ,Humans ,Lactic Acid ,Pulmonary Wedge Pressure ,Pulmonary wedge pressure ,education ,Aged ,Retrospective Studies ,Heart Failure ,education.field_of_study ,Ejection fraction ,business.industry ,Central venous pressure ,Hemodynamics ,Middle Aged ,medicine.disease ,Peptide Fragments ,medicine.anatomical_structure ,Heart failure ,Creatinine ,Cardiology ,Vascular resistance ,Female ,Vascular Resistance ,Cardiology and Cardiovascular Medicine ,business ,Anaerobic exercise - Abstract
Background: Lactate is an end-product of anaerobic cell metabolism. Although it is believed to have prognostic significance in heart failure (HF), data on the pathomechanisms that lead to lactate accumulation are scarce. Aim: We aimed to determine the clinical, respiratory, biochemical, and haemodynamic correlates of lactate in HF. Methods: Patients diagnosed with HF hospitalised in a single cardiac centre, who underwent haemodynamic monitoring, were included in this retrospective analysis. Results: The population consisted of 93 patients (44 acute HF [AHF] and 49 chronic HF [CHF] cases). The mean age, left ventricular ejection fraction, and lactate level were 60 ± 13 years, 33% ± 17%, 1.4 ± 0.9 mmol/L, respectively. The mean cardiac index (CI), right atrial pressure (RAP) and pulmonary capillary wedge pressure (PCWP) were 2.2 ± 0.5 L/min/m 2 , 8.7 ± 6 mmHg, and 18 ± 6 mmHg, respectively. AHF patients had significantly higher RAP, heart rate (HR), and levels of N-terminal pro–B-type natriuretic peptide and creatinine, compared to the CHF group. Both HR and natriuretic peptide level were correlated with lactate. Among haemodynamic indices, lactate correlated with CI (r = –0.25, p = 0.01). We found no correlation between lactate and RAP (p > 0.05) or PCWP (p > 0.05). There was no relationship between lactate and peripheral blood gases. Lactate was strongly correlated with mixed venous oxygen saturation (svO2) (r = –0.61, p < 0.05). HR, svO2, and systemic vascular resistance (SVR) were found to be independent determinants of lactate. Conclusions: Lactate accumulation in HF is not a result of respiratory disturbances or hypoxaemia. Among haemodynamic indices, CI is correlated with lactate. The strongest determinants of lactate included svO2, SVR, and HR.
- Published
- 2018
43. Control of Wind Turbine System with PMSG for Low Voltage Ride Through
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Krzysztof Pieńkowski and Piotr Gajewski
- Subjects
Mechanical system ,Test bench ,Computer science ,Voltage sag ,Permanent magnet synchronous generator ,AC power ,Low voltage ride through ,Turbine ,Automotive engineering ,Voltage - Abstract
In the paper the advanced control scheme of the wind turbine with PMSG (Permanent Magnet Synchronous Generator) is described. The direct-driven mechanical system of wind turbine and generator is considered. The issues of Low-Voltage Ride-Through (LVRT) are in particular analyzed. During the grid voltage sags, the control schemes of Machine Side Converter (MSC) and Grid Side Converter (GSC) are forced to meet the LVRT requirements. In order to keep the constant DC-link voltage during voltage sag, the surplus active power is storing in the mechanical system inertia of the wind turbine. To validate the effectiveness of the proposed control, scheme the experimental studies have been performed in the test bench. On the basis of experimental research, good operation of the considered voltage sag control of system has been demonstrated.
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- 2018
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44. Propagation models in radio environment map design
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Piotr Gajewski
- Subjects
Computer science ,Wireless network ,010401 analytical chemistry ,Transmitter ,Real-time computing ,020206 networking & telecommunications ,02 engineering and technology ,USable ,01 natural sciences ,Signal ,Dynamic spectrum management ,0104 chemical sciences ,Cognitive radio ,0202 electrical engineering, electronic engineering, information engineering ,Radio frequency ,Reflection mapping - Abstract
Radio Environment Map is a very important element of Dynamic Spectrum Management. It is used by spectrum regulators, wireless networks planners, operators, and Cognitive Radio users. REM is an information system, in which the electromagnetic field strength in every space location for whole usable spectrum is a main data to evaluate spectrum occupancy, and then for quality of signal reception. This data can be obtaining from expensive measurement campaigns, or/and as a prediction of signal sent by known radio transmitters. For such prediction, various propagation models can be used. Two main questions are discussed in this paper. The first one is an impact of used propagation models, and the second one is a digital map accuracy.
- Published
- 2018
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45. Asymmetric Transfer Hydrogenation of Ketones with Modified Grubbs Metathesis Catalysts: On the Way to a Tandem Process
- Author
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Marc Renom-Carrasco, Umberto Piarulli, Cesare Gennari, Piotr Gajewski, Laurent Lefort, Johannes G. de Vries, and Luca Pignataro
- Subjects
010405 organic chemistry ,Chemistry ,Organic Chemistry ,tandem catalysis ,Enantioselective synthesis ,asymmetric catalysis ,metathesis ,ruthenium ,transfer hydrogenation ,Catalysis ,Noyori asymmetric hydrogenation ,010402 general chemistry ,Metathesis ,Transfer hydrogenation ,01 natural sciences ,0104 chemical sciences ,3. Good health ,chemistry.chemical_compound ,Organic chemistry ,Ring-opening metathesis polymerisation ,Acyclic diene metathesis ,Acetophenone - Abstract
Herein, we report the successful transformation of a 1(st) generation Grubbs metathesis catalyst into an asymmetric transfer hydrogenation (ATH) catalyst. Upon addition of a chiral amine ligand, an alcohol and a base, the 1(st) generation Hoveyda-Grubbs catalyst (HG-I) was found to promote the enantioselective reduction of acetophenone to 1-phenylethanol. After optimizing the order of addition and the reaction conditions, the substrate scope was assessed leading to enantiomeric excesses up to 97% ee. NMR experiments were run in order to get information about the in situ-generated ATH catalyst. Furthermore, the possibility to perform olefin metathesis and ketone transfer hydrogenation sequentially in one pot was demonstrated, and the first tandem olefin metathesis-ketone asymmetric transfer hydrogenation was carried out.
- Published
- 2016
- Full Text
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46. Synthesis of (R)-BINOL-Derived (Cyclopentadienone)iron Complexes and Their Application in the Catalytic Asymmetric Hydrogenation of Ketones
- Author
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Sofia Vailati Facchini, Laurent Lefort, Luca Pignataro, Umberto Piarulli, Raffaella Ferraccioli, Marc Renom-Carrasco, Johannes G. de Vries, Piotr Gajewski, and Cesare Gennari
- Subjects
Trimethylsilyl ,Organic Chemistry ,Asymmetric hydrogenation ,Enantioselective synthesis ,Noyori asymmetric hydrogenation ,Homogeneous catalysis ,Reductive amination ,Medicinal chemistry ,Catalysis ,chemistry.chemical_compound ,chemistry ,Organic chemistry ,Organic synthesis ,Physical and Theoretical Chemistry - Abstract
A family of chiral (cyclopentadienone)iron complexes, featuring an (R)-BINOL-derived backbone, and their application in the asymmetric hydrogenation of ketones are described. The complexes differ from each other in the substituents at the 3,3-positions of the binaphthyl residue (H, OH, OR, OCOR, OSO2R) or at the 2,5-positions of the cyclopentadienone ring [trimethylsilyl (TMS) or Ph]. Remarkably, eight precatalysts with different 3,3-binaphthyl substitution [(R)-1c-1j] were synthesized from a common parent complex [(R)-1b] through direct functional group interconversion reactions of the complexes. The 3,3-(bis)methoxy-substituted precatalyst (R)-1b gave the best catalytic performance, and its application scope was assessed in the hydrogenation of several ketones. The observed ee values (up to 77%) are much higher than those previously reported for other chiral (cyclopentadienone)iron complexes.
- Published
- 2015
- Full Text
- View/download PDF
47. Assisted Tandem Catalysis: Metathesis Followed by Asymmetric Hydrogenation from a Single Ruthenium Source
- Author
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Cesare Gennari, Piotr Gajewski, Marc Renom-Carrasco, Luca Pignataro, Laurent Lefort, Johannes G. de Vries, Umberto Piarulli, and Synthetic Organic Chemistry
- Subjects
DECOMPOSITION ,TRANSFORMATIONS ,tandem catalysis ,Noyori asymmetric hydrogenation ,chemistry.chemical_element ,OLEFIN METATHESIS ,Ring-closing metathesis ,Ring-opening metathesis polymerisation ,Organic chemistry ,TETRASUBSTITUTED OLEFINS ,ruthenium ,asymmetric catalysis ,hydrogenation ,metathesis ,SOLVENT ,RING-CLOSING METATHESIS ,Chemistry ,Asymmetric hydrogenation ,Chiral ligand ,Enantioselective synthesis ,General Chemistry ,Combinatorial chemistry ,Ruthenium ,COMPLEXES ,LIGAND ,Acyclic diene metathesis - Abstract
Here we report the first example of a tandem metathesis-asymmetric hydrogenation protocol where the prochiral olefin generated by metathesis is hydrogenated with high enantioselectivity by an in situ formed chiral ruthenium catalyst. We show that either the ruthenium metathesis catalysts or the ruthenium species formed during the metathesis reaction can be converted into an efficient asymmetric hydrogenation catalyst upon addition of a chiral ligand and an alcohol. The performance in asymmetric hydrogenation appears to be very dependent on the solvent, the chiral ligand, and the prochiral substrate.
- Published
- 2015
- Full Text
- View/download PDF
48. Chiral (Cyclopentadienone)iron Complexes for the Catalytic Asymmetric Hydrogenation of Ketones
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Sofia Vailati Facchini, Alessandra Forni, Raffaella Ferraccioli, Umberto Piarulli, Luca Pignataro, Piotr Gajewski, Laurent Lefort, Marc Renom-Carrasco, Cesare Gennari, and Johannes G. de Vries
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Stereochemistry ,Chemistry ,Organic Chemistry ,Asymmetric hydrogenation ,Enantioselective synthesis ,Homogeneous catalysis ,Medicinal chemistry ,Reductive amination ,Catalysis ,Metal ,visual_art ,visual_art.visual_art_medium ,Moiety ,Reactivity (chemistry) ,Physical and Theoretical Chemistry - Abstract
Three chiral (cyclopentadienone)iron complexes derived from (R)-BINOL (CK1-3) were synthesized and their structures unambiguously confirmed by X-ray analysis (CK3). Under suitable conditions for the in situ conversion into the corresponding (hydroxycyclopentadienyl)iron hydrides (Me3NO, H-2), the new chiral complexes were tested in the catalytic asymmetric hydrogenation of ketones, showing moderate to good enantioselectivity. In particular, the complex bearing methoxy substituents at the 3,3-positions of the binaphthyl moiety (CK2) proved remarkably more enantioselective than the unsubstituted one (CK1) and reached the highest level of enantioselectivity (up to 77% ee) ever obtained with chiral (cyclopentadienone)iron complexes.
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- 2015
- Full Text
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49. ADAPTATION OF ENGINEERING FEA-BASED ALGORITHMS TO LCF FAILURE AND MATERIAL DATA PREDICTION IN OFFSHORE DESIGN
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Marek Augustyniak, Krzysztof Świątek, and Piotr Gajewski
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Engineering ,business.industry ,Mechanical Engineering ,Context (language use) ,Structural engineering ,Material data ,Finite element method ,Software ,high-strength steel ,Finite Element Method ,low-cycle fatigue ,Range (statistics) ,Submarine pipeline ,stress gradient influence ,business ,Engineering design process ,Adaptation (computer science) ,Algorithm - Abstract
There is an ever growing industrial demand for quantitative assessment of fatigue endurance of critical structural details. Although FEA-based calculations have become a standard in engineering design, problems involving the Low-To-Medium cycle range (101-104) remain challenging. This paper presents an attempt to optimally choose material data, meshing density and other algorithm settings in the context of recent design of the large offshore windfarm installation vessel, VIDAR. In this study, an attempt is made to assess default FEA-based procedures in RADIOSS software by comparing an experimental test against numerical analyses. Standard slender cylindrical (“I”) samples as well as originally designed “Z”-shaped samples made of A90 (S690)-grade steel have been loaded at various nominal stress ranges with or without local yielding. A good correlation has been found between FEA results and experimental cycles-to-failure in I-shaped samples, provided the softwarematerial data generator is avoided and Smith-Watson-Topper mean stress correction is used. In the case of Z-shaped samples, the calculated cycles-to-initiation of macro-crack is significantly lower (factor of 3) from the experiment. The observed discrepancy is argued to be due to stress gradient influence.
- Published
- 2017
50. MANET Cognitive Radio realtime testbed for dynamic spectrum access
- Author
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Jerzy Lopatka and Piotr Gajewski
- Subjects
Engineering ,business.industry ,ComputerSystemsOrganization_COMPUTER-COMMUNICATIONNETWORKS ,010401 analytical chemistry ,Spectrum (functional analysis) ,Testbed ,020206 networking & telecommunications ,Jamming ,02 engineering and technology ,Mobile ad hoc network ,01 natural sciences ,0104 chemical sciences ,Cognitive radio ,RF switch matrix ,0202 electrical engineering, electronic engineering, information engineering ,Radio frequency ,business ,Computer network - Abstract
The paper describes the MANET Cognitive Radio test bed. The proposed architecture consists of a number of CR nodes connected to the RF Switch Matrix, and enables simulation, scenario definition and management. Proposed procedures for Opportunistic Spectrum Access in MANET CR are described as well and chosen results of simulations obtained during laboratory tests are presented. The performance of these solution makes them fit for use in special and military applications.
- Published
- 2017
- Full Text
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