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Search results for: CHEMICAL POLYMERISATION
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Modeling and optimization of chemical-treated torrefaction of wheat straw to improve energy density by response surface methodology
PublicationToday, torrefaction is important technique for extending the potential of biomass for improvement of energy density. The independent variables investigated for torrefaction study were temperature, retention time, acid concentration, and particle size. The experiment was designed by central composite design (CCD) method using design expert (version 11). The three dependent variables were higher heating value (HHV), energy enhancement...
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Amperometric sensing of chemical oxygen demand at glassy carbon and silicon electrodes modified with boron-doped diamond
Publication.A boron-doped diamond (BDD) sensor is proposed for effective detection of chemical oxygen demand (COD) by means of amperometric technique. Boron-doped diamond thin films, acting as active sensors, were deposited on both silicon wafer and glassy carbon (GC) substrates by microwave plasma assisted chemical vapour deposition. SEM micrographs showed that BDD–Si displays triangle-faceted crystallites ca. 0.5–3 μm in size, while BDD–GC...
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Analysis of chemical composition and hardness of copper alloys = Badania składu chemicznego oraz twardości stopów miedzi
PublicationWykonano analizę składu chemicznego oraz badania twardości stopów miedzi zastosowanych na elementy łożyskowe. Sformułowano wnioski.
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Chemical kinetic approach to the mechanism of coupled transport of Cu(II) Ions through bulk liquid membranes
PublicationW celu lepszego zrozumienia transportu jonów miedzi przez ciekłe membrany zaproponowano schemat kinetyczny na poziomie molekularnym oparty o dwie nastepujące po sobie reakcje odwracalne. Zasegurowano uzywając membrany ciekłej o wysokiej polarności i polaryzowalności oraz szybkiego mieszania mozna zwiekszyć wydajnośc transportu.
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The changes of crosslink density of polyurethanes synthesised with using recycled component. Chemical structure and mechanical properties investigations.
PublicationThis paper aims at the utilisation of glycerolysate (Gly) obtained in polyurethane recycling process by means of crude glycerine, which has in its structure hydroxyl end groups that allow for further processing. Polyurethanes (PUs) were synthesised using prepolymer method with the mixture of neat polyol and glycerolysate, in different ratios, with 4,4-diphenylmethane diisocyanate (MDI). The prepolymer was subsequently extended...
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Synthesis, Chemical Characterization and Multiscale Biological Evaluation of a dimericcRGD Peptide for Targeted Imaging of αVβ3 Integrin Activity
PublicationCyclic peptides containing the Arg-Gly-Asp (RGD) sequence have been shown to specifically bind the angiogenesis biomarker α V β3 integrin. We report the synthesis, chemical characterization, and biological evaluation of two novel dimeric cyclic RGD-based molecular probes for the targeted imaging of α V β3 activity (a radiolabeled version, 64Cu-NOTA-PEG4-cRGD2, for PET imaging, and a fluorescent version, FITC-PEG4-cRGD2, for in...
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Electroactive polymer/graphene oxide nanostructured composites; evidence for direct chemical interactions between PEDOT and GOx
PublicationThis work concerns electrochemical synthesis of nanocomposites consisting of conducting polymer and reduced graphene oxide (rGOx) as electrode materials for supercapacitors. The electrosynthesis was performed in an aqueous solution of the 3,4-ethylenedioxytiophene (EDOT) monomer and graphene oxide (GOx) without supporting electrolyte. The amount of GOx was optimized to obtain the best electrochemical performance of the nanocomposite...
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Peptide conjugates of lactoferricin analogues and antimicrobials—Design, chemical synthesis, evaluation of antimicrobial activity and mammalian cytotoxicity
PublicationEight new peptide conjugates composed of modified bovine lactoferricin truncated analogues (LFcinB) and oneof the three antimicrobials — ciprofloxacin (CIP), levofloxacin (LVX), and fluconazole (FLC) — were synthesized. Four different linkers were applied to connect a peptide and an antimicrobial agent. The FLC-containing peptidic conjugates were synthesized using the “click chemistry” method. This novel approach is reported here...
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Chemical composition of shells from red (Strongylocentrotus franciscanum) and green (Strongylocentrotus droeba-chiensis) sea urchin
PublicationThe shells from red and green sea urchins accounted for 47.9 and 40.7% of their body weights, respectively. The red and green sea urchin shells contained 91.08 and 90.77% minerals and 4.06 and 4.99% proteins, respectively. The shells did not contain any chitin. Sea urchin shells had a relatively large amount of naphthoquinone pigments, 121 mg per 100 g in red and 163 mg per 100 g in green species. The small quantities of glucosamine...
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Determination of Chemical Oxygen Demand (COD) at Boron-doped Diamond (BDD) Sensor by Means of Amperometric Technique
PublicationA boron-doped diamond (BDD) sensor was proposed for effective detection of chemical oxygen demand (COD) by means of amperometric technique. Thin boron doped diamond active sensor layer was deposited on Si wafer and glassy carbon substrate by Microwave Plasma Enhanced Chemical Vapor Deposition (MW PE CVD). The structure of BDD was confirmed by Raman spectra analysis. Broad Raman bands centered at 482 cm-1 and 1219 cm-1 are typical...
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Currently Commercially Available Chemical Sensors Employed for Detection of Volatile Organic Compounds in Outdoor and Indoor Air
PublicationThe paper presents principle of operation and design of the most popular chemical sensors for measurement of volatile organic compounds (VOCs) in outdoor and indoor air. It describes the sensors for evaluation of explosion risk including pellistors and IR-absorption sensors as well as the sensors for detection of toxic compounds such as electrochemical (amperometric), photoionization and semiconductor with solid electrolyte ones....
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Chemia w praktyce - wskaźniki
PublicationW nauczaniu chemii na każdym etapie kształcenia warto eksponować eksperymentalny charakter tej nauki. Doświadczenia przeprowadzane na lekcji pełnią nie tylko funkcję ilustracyjną, badawczą bądź weryfikacyjną, ale mogą też odegrać istotną rolę motywacyjną. Praktycznie każdy, nawet bardzo skromny i prosty, ale dobrze zaplanowany eksperyment pozwala poszerzyć wiedzę i zrobić to w sposób najlepszy z możliwych. Przedstawiony w pracy...
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Chemia analityczna w lipidomice
PublicationLipidomika, stanowiąca gałąź metabolomiki, jest prężnie rozwijającą się dziedziną nauki, w której badania ukierunkowane są na identyfikację oraz oznaczenie ilościowe lipidów komórkowych, poznanie ich funkcji biologicznych oraz oddziaływań z innymi cząsteczkami. Wzrost zainteresowania badaniami lipidomicznymi w ostatnich latach, zwłaszcza w obszarze tworzenia profili lipidów komórkowych, związany był z wprowadzeniem do praktyki...
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Nanotechnologia, chemia i medycyna
PublicationKsiążka przedstawia chemiczne metody otrzymywania nanomateriałów oraz metody ich funkcjonalizacji. Opisano struktury zero, jedno i dwuwymiarowe zbudowane z różnych materiałów (metale, ceramika, związki organiczne, alotropowe odmiany węgla, chalkogenki metali). Podano wybrane przykłady zastosowania nanostruktur w medycynie i naukach pokrewnych.
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Zintegrowany system badań zanieczyszczenia środowiska oparty na wykorzystaniu analityki chemicznej i biotestów = Integrated system for assessment of environment quality based on chemical analysis and biotests/Integrated system for assessment of environment quality based on chemical analysis and biotests/
PublicationW ostatnich latach coraz częściej do oceny jakości środowiska wykorzystuje się tzw. narzędzia zintegrowane, czyli połączenie analiz chemicznych z mikrobiotestami. Umożliwić to ma identyfikację potencjalnych źródeł toksyczności w analizowanych próbkach. Niestety, znalezienie wyraźnych korelacji pomiędzy wynikami analiz chemicznych oraz oszacowanymi parametrami toksyczności nie jest prostym zadaniem i nastręcza wiele trudności.
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Magnetic semiconductor photocatalysts for the degradation of recalcitrant chemicals from flow back water
PublicationIn the present study treatability of persistent organic compounds from the flow back water after hydrauling fracturing was investigated. The combination of TiO2 photocatalyst and magnetic oxide nanoparticles enhance the separation and recoverable property of nanosized TiO2 photocatalyst. Fe3O4/ TiO2 and Fe3O4@SiO2/TiO2 nanocomposites were prepared by heteroagglomeration. The photocatalysts’ characteristics by X-ray diffractometry...
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Preparation and characterization of Pt–N/TiO2 photocatalysts and their efficiency in degradation of recalcitrant chemicals
PublicationSeries of Pt–N/TiO2 photocatalysts were synthesized using the sol–gel method. The photocatalysts’ characteristics by X-ray diffractometry (XRD), scanning transmission electron microscopy (STEM), diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) showed that sample with the molar ratio Ti:N equal 1:4 and platinum nanoparticles size of about 3 nm had anatase structure, about 94 m2/g specific surface area...
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Determination of Toxicological Parameters of Selected Bioactive Organic Chemicals Using the Ostracodtoxkit FTM
PublicationAssessment of the impact of pharmaceutical residues on living organisms is very complex subject. Apart from taking into account the toxicity of individual compounds also their presence in mixtures should be taken into account. In this work, attempts were made to assess the ecotoxicity of biologically active substances (with 50 % effective concentration (EC50) values growing from fluoxetine (EC50 = 4.431 nM) >> gemfibrozil ≈ 17α-ethinylestradiol...
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Modification of cellulosic filler with diisocyanates – volatile organic compounds emission assessment and stability of chemical structure over time
PublicationThis paper investigated the impact of type and content of diisocyanate on the structure of modified cellulose fillers. Four the most popular isocyanates were applied – isophorone, hexamethylene, toluene and methylene diphenyl diisocyanate – at loadings of 1–15 wt%. Chemical structure, and its short-term storage stability, were investigated for eight weeks. Moreover, the main volatile organic compounds detected during modification,...
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Interactions between polyphenolic antioxidants quercetin and naringenin dictate the distinctive redox-related chemical and biological behaviour of their mixtures
PublicationFood synergy concept is suggested to explain observations that isolated antioxidants are less bioactive than real foods containing them. However, mechanisms behind this discrepancy were hardly studied. Here, we demonstrate the profound impact of interactions between two common food flavonoids (individual: aglycones quercetin—Q and naringenin—N− or their glycosides rutin—R and naringin—N+ vs. mixed: QN− and RN+) on their electrochemical...
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Effect of bio-based components on the chemical structure, thermal stability and mechanical properties of green thermoplastic polyurethane elastomers
PublicationIt seems to be obvious that conditions changes during polyols synthesis have impact on the polyols properties. Even the chemical formula is the same or similar, physicochemical properties and also molecular weight of polyols might be different and are significant in term of future polyurethanes properties and processing. In this work, fully bio-based poly(propylene succinate)s synthesized at different temperature conditions were...
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Chemical and biological evaluation of antioxidant activity of endogenous redox-active compounds compared to plant-derived exogenous antioxidants
PublicationThe research conducted so far has shown that endogenous antioxidants, despite being regarded as the first line of antioxidant defense, may not be sufficient to maintain redox homeostasis in cells exposed to oxidative stress. The results obtained in the doctoral dissertation show that endogenous redox-active compounds were moderate or weak scavengers of ABTS and DPPH radicals, while in cellular setting, their impact on the reducing...
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Influence of the Tool Rotational Speed on Physical and Chemical Properties of Dissimilar Friction-Stir-Welded AA5083/AA6060 Joints
PublicationAluminum alloys have been successfully used in the railroad and automotive industries because of their potential to significantly reduce component weights, and their good mechanical and anti-corrosion properties. Problems with joining aluminum alloys are characterized by low weldability, which influences the need for studies focused on unconventional methods. The environmentally friendly and low-cost friction-stir-welding method...
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Influence of Phosphorus Speciation on Its Chemical Removal from Reject Water from Dewatering of Municipal Sewage Sludge
PublicationThe aim of the presented research was the assessment of phosphorus speciation impact on the precipitation of phosphorus in reject water using Ca(OH)2. To achieve this, phosphorus speciation (organic and inorganic phosphorus in suspension and in dissolved form) in reject water that is produced during sludge dewatering, after methane digestion in wastewater treatment plants (WWTPs), was determined. This study covered the materials...
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Chemical surface etching methods for ground tire rubber as sustainable approach for environmentally-friendly composites development– a review
PublicationGround tire rubber (GTR) has been used as a sustainable low-cost modifier in various composites. However, due to the hydrophobic nature of GTR, it is in compatible with most matrices and results in deterioration in both mechanical and physical properties of composites. This necessitates pre-modification of the powdered rubber to improve the interfacial bonding at the rubber-matric interface. The most common GTR modification research...
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Morphological, genetic, chemical and ecophysiological characterisation of two Microcystis aeruginosa isolates from the Vistula Lagoon, southern Baltic
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Chemical composition and antifungal activity of Chelidonium majus extracts – antagonistic action of chelerythrine and sanguinarine against Botrytis cinerea
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Physico‐chemical and proteolytic changes during cold storage of dry‐cured pork loins with probiotic strains ofLAB
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Chemical Composition and Antimicrobial Activity of Selected Essential Oils against Staphylococcus spp. Isolated from Human Semen
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Chemical Composition, Antioxidant, In Vitro and In Situ Antimicrobial, Antibiofilm, and Anti-Insect Activity of Cedar atlantica Essential Oil
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Influence of e-beam irradiation on the chemical and crystal structure of poly(aliphatic/aromatic-ester) multiblock thermoplastic elastomers
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Changes in chemical composition and oxidative stability of cold-pressed oils obtained from by-product roasted berry seeds
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Physico-Chemical Characterization and Biological Tests of Collagen/Silk Fibroin/Chitosan Scaffolds Cross-Linked by Dialdehyde Starch
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Mobility and bioavailability of mercury in sediments of the southern Baltic sea in relation to the chemical fractions of iron: Spatial and temporal patterns
PublicationMarine sediments play a significant role as reservoirs for mercury (Hg), a bioaccumulative toxic pollutant that poses risks to human and ecosystem health. Iron (Fe) has been recognized as an influential factor in the complexation and bioavailability of Hg in sediments. However, limited studies have investigated the interactions between the chemical fractions of these elements in natural settings. This study aims to examine the...
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Recent achievements in chemical hydride generation inductively coupled and microwave induced plasmas with optical emission spectrometry detection
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Quantum chemical modeling (DFT) of active species on the VWO catalyst surface in various redox conditions
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Estimation of Potential Leakage from Dumped Chemical Munitions in the Baltic Sea Based on Two Different Modelling Approaches
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Mobility and bioavailability of mercury in sediments of the southern Baltic sea in relation to the chemical fractions of iron: Spatial and temporal patterns
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Glycerol extracts of Glycyrrhiza glabra, Echinacea purpurea, Silybum marianum and Berberis vulgaris: chemical characterisation and cosmeceutical potential
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Comparison of antioxidant and enzyme inhibition activities as well chemical composition of different extracts and fractions of Rubus caesius leaves
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Investigation on structural, optical and anti-bacterial properties of organic additives iron oxide prepared by chemical route method
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Influence of retrogression and reaging (RRA) heat treatment on microstructure, mechanical and chemical behaviour of an Al-Zn-Mg alloy
PublicationBadano metodą stałego wolnego rozciągania w wodzie morskiej wpływ czasu i temperatury nawrotu oraz powtórnego starzenia na czas do zniszczenia, energię zniszczenia, przewężenie i odkształcenie. Stwierdzono ogólnie niewielki wpływ, przy czym wzrostowi odporności na korozję naprężeniową towarzyszył spadek właściwości mechanicznych. Obserwowane zmiany właściwości przypisano zmianom struktury dyslokacyjnej i mikrostruktury.
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Poly(3,4-ethynenedioxythiophene)-Prussian Blue hybrid material evidence of direct chemical interaction betwenn PB andpEDOT
PublicationPrzedstawiono syntezę materiału złożonego z poli(3,4-etylenodioksytiofenu) oraz analogu błękitu pruskiego. Sieć struktury BP utworzona została wewnątrz matrycy polimerowej pEDOT-u za pomocą metody polaryzacji multicyklicznej. Chemiczne oddziaływania Fe z BP oraz siarki z pEDOT zostały potwierdzone metodą XPS. Obecność BP potwierdzono FTiR - stwierdzono obecność drgań rozciągających Fe-C oraz Fe-N. Metoda cyklowoltamperometryczna...
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Tribo-Environment Dependent Chemical Modification of Sliding Interfaces in Ultrananocrystalline Diamond Nanowall Film: A Correlation with Friction and Wear
PublicationTribological properties of ultrananocrystalline diamond nanowall (UNCD NW) films were investigated quantitatively in three different and controlled tribo-environmental conditions, proposing the passivation and graphitization mechanisms. However, these mechanisms are rather complicated and possibly can be understood in well-controlled tribological conditions. It was shown that the friction and wear of these films were high in highPage 1...
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Determination of selected chemical parameters in surface water samples collected from the Revelva catchment (Hornsund fjord, Svalbard)
PublicationSurface water samples (river and lake) were collected from the Revelva catchment every summer from 2010 to 2013. This study concerns importance of the use of some analytical techniques for pollutants and parameters deter- mination in Arctic environmental samples based on the example of total organic carbon, phenols, and formaldehyde determination and measurement of pH and electrical conductivity parameters. Significant...
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Dissolved and colloidal organic nitrogen removal from WWTP effluents and reject waters using physical-chemical processes
PublicationFour physical-chemical processes were compared in terms of the efficiencies of dissolved and colloidal organic nitrogen (DON and CON) removal from the secondary effluents (SE) and reject water from full-scale biological nutrient removal activated sludge systems. Adsorption on activated carbon was most efficient and allowed to remove from the SE up to 80% and 100% of DON and CON, respectively. High efficiencies of DON removal from...
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Determination of Chemical Diffusion Coefficient of Lithium Ions in Ceramics Derived from Pyrolysed Poly(1,2-dimethylsilazane) and Starch
PublicationThe apparent chemical diffusion coefficient Li+ (DappLI+) in pyrolysed poly(1,2-dimethylsilazane)/starch (PSN/S) (weight ratio: 30/70) ceramic anode composite is determined by galvanostatic intermittent titration technique (GITT). The electrode material composition is C6.00N0.14H0.47O0.12Si0.13. The calculated values of DappLI+, depend on the applied potential, vary from 10-14 to 10-9 [cm2/s]. The diffusion coefficient of lithium...
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Morphometric parameters of the Renardbreen as important factors determining the spatial distribution of chemical compounds on the glacier surface (Bellsund, Svalbard)
PublicationThis paper concern influence of the morphometric parameters (height, length and slope of the glacier) on the spatial distribution of the physicochemical parameters (pH, electrical conductivity, total organic carbon) determined in the ice and snow samples collected from the surface of Renardbreen during summer season of 2012. Obtained results allow to assume also a significant changes in a spatial distribution of other chemical...
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Chemical structures, rheological and physical properties of biopolyols prepared via solvothermal liquefaction of Enteromorpha and Zostera marina biomass
PublicationIn this work, liquefied biomass from the Baltic Sea was used for the preparation of rigid polyurethane (PUR) foams. The biomass contained 10 wt% of Enteromorpha macroalgae and 90 wt% of Zostera marina seagrass characterized by a high content of cellulose. The influence of time, temperature and the type of solvent on the efficiency of the liquefaction process and properties of biopolyols was determined. Obtained materials were analyzed...
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Two-step Conversion of Crude Glycerol Generated by Biodiesel Production into Biopolyols: Synthesis, Structural and Physical Chemical Characterization
PublicationIn this work biopolyols were synthesized via two-step process from crude glycerol and castor oil. For better evaluation of analyzed process, the impact of its time and temperature on the structure and properties of biopolyols was determined. Obtained results fully justified conducting of synthesis in two steps. Prepared materials were characterized by hydroxyl value and water content comparable to polyols industrially applied in...