Filtry
wszystkich: 3504
-
Katalog
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: SEPARATION OF CONCERNS
-
Improved chromatography separation for polybrominated diphenyl ether congeners quantification in the food of animal origin
Publikacja -
A selection of the optimal eluent components for separation of carnivorous plants metabolites by planar chromatography chromatography
PublikacjaAbstract: The development of the new procedures of the separation components with the complicated chemical structure from natural complex matrix by column chromatography is very difficult and in many cases expensive. Therefore to pre-select the conditions of the separation process the use of thin layer chromatography (TLC) is proffered. The possibility of proceeding the chromatographic process for several mixtures on single plate,...
-
pH Gradient as a Tool for the Separation of Ionizable Analytes in Reversed-Phase High-Performance Chromatography
Publikacja -
Separation of anthocyanins from black carrot, chokeberry, blackcurrant, and elderberry with the use of preparative chromatography
Publikacja -
Polyether-block-amide PEBA membranes for gas separation and pervaporation; current design and applications
PublikacjaPolyether-block-amide (PEBA) membranes have attracted considerable attention for their exceptional efficacy in gas separation and pervaporation processes. This comprehensive review delves into the precise definition, distinguishing characteristics, and diverse applications of PEBA membranes over the past five years. A primary research objective focuses on enhancing gas separation efficiency, primarily through augmenting membrane...
-
Green porous benzamide-like nanomembranes for hazardous cations detection, separation, and concentration adjustment
PublikacjaGreen biomaterials play a crucial role in the diagnosis and treatment of diseases as well as health-related problem-solving. Typically, biocompatibility, biodegradability, and mechanical strength are requirements centered on biomaterial engineering. However, in-hospital therapeutics require an elaborated synthesis of hybrid and complex nanomaterials capable of mimicking cellular behavior. Accumulation of hazardous cations like...
-
Ongoing progress on novel nanocomposite membranes for the separation of heavy metals from contaminated water
PublikacjaMembranes, as the primary separation element of membrane-based processes, have greatly attracted the attention of researchers in several water treatment applications, including wastewater treatment, water purification, water disinfection, toxic and non-toxic chemical molecules, heavy metals, among others. Today, the removal of heavy metals from water has become challenging, in which chemical engineers are approaching new materials...
-
CO2 Separation Using Supported Deep Eutectic Liquid Membranes Based on 1,2-propanediol
PublikacjaIn this work, deep eutectic solvents (DESs) composed of choline chloride, acetylcholine chloride or tetrabutylammonium chloride, and 1,2-propanediol were used as a liquid phase for polypropylene-based supported liquid membranes (SLMs) and evaluated for the separation of carbon dioxide from CO2/N2 mixtures. Fourier transform infrared spectra were obtained to confirm DES formation, and the thermal stability of solvents was investigated...
-
Evaluation of the usefulness and optimization of the separation conditions in Empty Column Gas Chromatography (EC-GC)
PublikacjaDotychczasowe badania wykazały, że możliwe jest rozdzielanie wysokowrzących mieszanin techniką chromatografii gazowej z zastosowaniem pustej rurki kapilarnej z topionej krzemionki, zamiast kolumn zawierających fazę stacjonarną. Operacja rozdzielania chromatograficznego ma miejsce jedynie na zasadzie różnicy temperatur wrzenia rozdzielanych substancji. Wysoki stopień podobieństwa warunków rozdzielania, osiąganych w ten sposób, z...
-
Phase separation in poly(butylene terephthalate)-based materials prepared by solid-state modification
PublikacjaThe morphology of a series of poly(butylene terephthalate) (PBT)/fatty acid dimer diol (FADD)-based copolyesters prepared by solid-state modi fi cation (SSM) was studied. It was shown that in copolyesters containing less than 10 wt% FADD two different phases, i.e. a PBT crystalline phase and a PBT-rich amorphous phase, are present. The FADD residues were more or less homogeneously distributed throughout the interlamellar regions....
-
Separation of toluene from gas phase using supported imidazolium ionic liquid membrane
PublikacjaInvestigation on utilization of supported ionic liquids membranes for hydrocarbon separation from the gas phase was performed. Properties of membrane phase, wettability of supports, swelling effects and solubility of toluene were taken into account. Toluene permeation rates were significantly higher than those of pure nitrogen, the selectivity in a range of 17–341 was satisfying for separation. Despite the increase of viscosity...
-
The Application of Cellulose Acetate Membranes for Separation of Fermentation Broths by the Reverse Osmosis: A Feasibility Study
Publikacja -
Distribution of relaxation times as a method of separation and identification of complex processes measured by impedance spectroscopy
PublikacjaImpedance spectroscopy is one of the most commonly performed measurements to characterize electronic and electrochemical systems. Impedance spectra have limited resolution and many different processes may overlap what could be the reason of obstructions in its proper later analysis. Up to date, there are three approaches to solve this problem: examining impedance spectra itself, fitting spectra with equivalent circuits, and calculating...
-
Optimal selection of the sawdust separation device for a narrow-kerf sawing machine PRW15-M
PublikacjaW pracy przedstawiono granulometryczną analizę rozkładu wiórów i pyłu drzewnego otrzymanego w procesie przecinania suchych pryzm sosnowych na pilarce ramowej wielopiłowej PRW15-M. Wielkości wiórów mieściły się w granicach od 84,7 μm do nawet 14 mm. Te ostatnie są elementami będącymi efektem rozszczepiania dolnej powierzchni pryzmy przez wychodzące z niej ostrza piły. Większośc wiórów z najmniejszych frakcji ma postać sześciennych...
-
Musical instrument sound separation methods supported by artificial nueural network decision system
PublikacjaRozprawa doktorska (27 czerwica 2006).Celem prowadzonych prac badawczych było opracowanie algorytmów separacji dźwięków instrumentów muzycznych. Dodatkowo dobrano zestaw parametrów tak aby możliwe było wytrenowanie sztucznej sieci neuronowej w celu automatycznego rozpoznawania odseparowanych sygnałów. Zaproponowano również aby algorytm decyzyjny odpowiedzialny za klasyfikacje dźwięków pełnił funkcję automatycznej metody oceny algorytmów...
-
SEPARATION AND PURIFICATION REVIEWS
Czasopisma -
Preparation and characterization of rigid polyurethane-polyglycerolnanocomposite foams
PublikacjaThis work reports on the preparation of polyurethane-polyisocyanurate (PUR-PIR) foams containing different polyglycerols and layered silicate nanoclays. The rigid polyurethane foams were obtained in a laboratory scale, in a single step method, from a two-component system with a NCO to OH groups ratio equal to two. The reaction mixture consisted of the proper amounts of a commercial oligoetherpolyol, polyglycerol, catalysts, water,...
-
Preparation of colloidal silver in W/O microemulsion
PublikacjaStabilne koloidy srebra otrzymano poprzez redukcję azotanu srebra w mikroemulsji dodekan-woda-AOT. Otrzymane zawiesiny nanocząstek srebra w dodekanie wykazywały stabilność w czasie, tj. nie zmieniały właściwości przez kilka miesięcy. Stwierdzono, że stabilność otrzymanych roztworów koloidalnych nie zależy od stężenia srebra w zakresie od 60 do 1000 mg/dm3, natomiast silnie zależy od stężenia surfaktanta. Niska toksyczność dodekanu,...
-
A new and convenient method for the preparation of functionalized phosphorothioates
PublikacjaA new and efficient method for the synthesis of alkyl and aryl phosphorothioates in high yields via the reaction of (5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorin-2-yl)disulfanyl derivatives with trimethyl phosphite was developed.
-
A versatile and convenient preparation of unsymmetrical diaryl disulfides
PublikacjaWe have developed a convenient method for the synthesis of unsymmetrical diaryl disulfides under mild conditions in excellent yields. The described method is based on the straightforward preparation of 5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinane-2-sulfenyl bromide from readily available 5,5-dimethyl-2-thiolo-2-thioxo-1,3,2-dioxaphosphorinane or bis(5,5-dimethyl-2-thioxo-1,3,2-dioxaphosphorinan-2-yl) disulfide. The unsymmetrical...
-
Preparation of samples for analysis: the key to analytical success
PublikacjaW rozdziale przedstawiono informacje literaturowe o nowych rozwiązaniach metodycznych w zakresie:-izolacji i/lub wzbogacania śladowych składników z próbek środowiskowych-mineralizacji próbek.Szczególna uwagę zwrócono na wykorzystanie w procesie przygotowania próbek nowych typów rozpuszczalników i mediów reakcyjnych spełniających wymogi związane z koncepcją zrównoważonego rozwoju.
-
Green Analytical Chemistry Approaches in Sample Preparation
PublikacjaThis chapter presents environmentally friendly solutions for sample preparation. Attention is focused on extraction techniques and the minimization of organic solvent consumption, as the large quantitiesused in analytical laboratories are a pressing environmental problem. Solventless sample preparation techniques, alternative solvents, mediated extractions are discussed. The principle of each technique isbriefly described, together...
-
Modern Sample Preparation Techniques: A Brief Introduction
Publikacja -
Polyurethane-based aerogels: Preparation, properties, and applications
PublikacjaPolyurethane aerogels (PUAs) are interesting materials because of their high porosity, low density, and low thermal conductivity, which result in their application as thermal insulations. PUAs are mainly synthesized using di- and polyisocyanates, diols or polyols, catalysts (tertiary amines and organometallic), and solvents (which are used as reaction medium, purifying of obtained semiproducts). Preparation procedure involves several...
-
Oxidation step in the preparation of benzocamalexin: The crystallographic evidence
PublikacjaThe study of oxidation step in the preparation of benzocamalexin by the α-amidoalkylation–oxidation sequence revealed the formation of perchloro-1,2-phenylene dibenzoate as the product of transformation of tetrachloro- 1,2-benzoquinone applied as the oxidant. The structures of benzocamalexin and perchloro-1,2-phenylene dibenzoate were confirmed by X-ray diffraction analysis. The extraction step in the final isolation of benzocamalexin...
-
Green Aspects of Miniaturized Sample Preparation Techniques
PublikacjaCorrect monitoring and control of the state of the environment and scientific research on the subject of environmental protection often require that determinations of compounds present at very low concentrations be made in samples characterized by a matrix of complex composition (e.g., biological samples, water and soil samples). Moreover, due to the limited number of analytical techniques which are sufficiently sensitive to conduct...
-
Preparation of silver nanoparticles with controlled particle size
PublikacjaNanocząstki srebra wykazują zdolność absorpcji promieniowania widzialnego, która jest efektem istnienia powierzchniowego plazmonu. W zależności od kształtu i wielkości cząstek obserwuje się różną barwę koloidów srebra. W wyniku przeprowadzonych badań otrzymano nanocząstki srebra metodą chemicznej redukcji. Zaobserwowano wpływ rodzaju reduktora (kwas askorbinowy, borowodorek sodu), stabilizatora (PVP, PVA) oraz prekursora srebra...
-
Heteropolyanions doped polyimine—Preparation and spectroscopic properties
Publikacja -
Preparation and characterization of biopolymeric films with magnetic properties
Publikacja -
Preparation and characterisation of solution-cast Nafion membrane
PublikacjaNafion is a commercial name for a perfluorosulfonic polymer, which has been developed in 1962 by Dupont de Nemours. This polymer consists of a polytetrafluoroethylene backbone and regular spaced long perfluorovinyl ether pendant side chains terminated by a sulfonate ionic group. These sulfonate groups are responsible for cation-exchange properties of Nafion. Thanks to the ion-exchange properties, water permeability, good chemical,...
-
A new preparation method of catalyst for ammonia synthesis
Publikacja -
AGREEprep – Analytical greenness metric for sample preparation
PublikacjaThis work proposes for the first time, a metric tool that gives prominence to sample preparation. The developed metric (termed AGREEprep) was based on 10 categories of impact that were recalculated to 0 e1 scale sub-scores, and then used to calculate the final assessment score. The criteria of assessment evaluated, among others, the choice and use of solvents, materials and reagents, waste generation, energy consumption, sample...
-
Preparation of samples of plant material for chromatographic analysis
PublikacjaPrzedstawiono informacje literaturowe nt. etapów przygotowania próbek materiału roślinnego do analizy chromatograficznej. Szczególną uwagę zwrócono na techniki izolacji i/lub wzbogacenie analitów przed etapem oznaczeń końcowych, walidację stosowanych procedur, sposoby pobierania próbek celem określenia emisji biogenicznej lotnych związków organicznych.
-
Preparation and application of lecithin formulation in liquid detergents
PublikacjaBadano solubilizację odolejonej lecytyny rzepakowej w wodnych roztworach surfaktantów anionowych, kationowych i niejonowych. Najlepszymi solubilizatorami okazały się surfaktanty anionowe (dodecylosiarczan sodu i sól sodowa oksyetylenowanego siarczanowanego alkoholu tłuszczowego). Otrzymano jednorodne preparaty lecytynowe o zawartości lecytyny do 30% i zawartości surfaktantów anionowych do 20%. Preparat lecytyny i Sulforokanolu...
-
Design concepts of propulsion and steering system for hotel unit of two-segment inland waterways ship
PublikacjaW artykule przedstawiono założenia projektowe i dwa rozwiązania koncepcyjne napędu i sterowania barki hotelowej, stanowiącej część dwusegmentowego statku śródlądowego i przybrzeżnego. Obydwa rozwiązania oparto na zastosowaniu dziobowego śrubosteru małej mocy, ze śrubą stałą umieszczoną w dyszy obrotowej. W jednym z rozwiązań śruba napędzana jest silnikiem hydraulicznym, zaś w drugim - silnikiem elektrycznym. Mechanizm obrotu kolumny...
-
Thermodynamic Cycle Concepts for High-Efficiency Power Plans. Part A: Public Power Plants 60+
PublikacjaAn analysis was carried out for different thermodynamic cycles of power plants with air turbines. Variants with regeneration and different cogeneration systems were considered. In the paper, we propose a new modification of a gas turbine cycle with the combustion chamber at the turbine outlet. A special air by-pass system of the combustor was applied and, in this way, the efficiency of the turbine cycle was increased by a few points....
-
Equivalence of equicontinuity concepts for Markov operators derived from a Schur-like property for spaces of measures
PublikacjaVarious equicontinuity properties for families of Markov operators have been – and still are – used in the study of existence and uniqueness of invariant probability for these operators, and of asymptotic stability. We prove a general result on equivalence of equicontinuity concepts. It allows comparing results in the literature and switching from one view on equicontinuity to another, which is technically convenient in proofs....
-
Evidence of adaptation, niche separation and microevolution within the genus Polaromonas on Arctic and Antarctic glacial surfaces
Publikacja -
Application of chiral chromatography for enantiomeric separation of currently used pesticides from various chemical groups
PublikacjaChiral pesticides account for more than 25 % of currently used pesticides and this ratio is still increasing. According to the number of chiral centers in the structure, a pesticide may consist of two or multiple enantiomers or stereoisomers. Studies into the stereoselective behaviour of pesticides started in the early 1990s and most research efforts focused on understanding the environmental fate and effects of these pesticides....
-
Bayesian separation algorithm of THz spectral sources applied to D-glucose monohydrate dehydration kinetics
Publikacja -
A research on the optimal conditions for separation and identyfication of the components from the Droseraceae extracts by column liquid chromatography
PublikacjaThe isolation of the components with anticipated biological properties i.e. antimicrobial, fungicidal, antioxidant and perhaps anticancer activity is for many years a one of the biggest issues of modern separation science. Their obtaining based on the isolation of the components with the biological activity from in vitro cultured plants by extraction techniques is often more difficult than their production by the chemical synthesis.The...
-
Separation of surfactant functionalized single-walled carbon nanotubes via free solution electrophoresis method
Publikacja -
A Fast Method of Separation of the Noisy Background from the Head-Cross Section in the Sequence of MRI Scans
PublikacjaThe paper presents a new method of removing the noisy background from the sequence of magnetic resonance imaging (MRl) scans. The sequence of scans is required in order to monitor a passage of a contrast agent through the brain tissue. The scans contain the noisy head-cross data and also the noisy background data. The latter has to be removed and excluded from a further analysis. It is achieved by applying some basic morphological...
-
Recent advances in carbon-based renewable adsorbent for selective carbon dioxide capture and separation-A review
Publikacja -
Development of nanoscale morphology and role of viscoelastic phase separation on the properties of epoxy/recycled polyurethane blends
PublikacjaA novel and cost-effective approach towards the modification of epoxy matrix has been developed using recycled polyurethane for the first time without sacrificing any of the intrinsic properties of the resin. Polyurethane, recycled from waste foam by glycolysis process (RPU), was found to be very effective in improving the properties of the thermosetting resin based on Diglycidyl ether of bisphenol-A (DGEBA). The effect of the...
-
Evolutionary sets of safe ship trajectories with speed reduction manoeuvres within traffic separation schemes
PublikacjaIn the previous paper the author presented the evolutionary ship trajectory planning method designed to support Traffic Separation Schemes (TSS). This time the extensions of this method are described which allow to combine evolutionary trajectory planning with speed reduction manoeuvres. On TSS regions with higher than usual density of traffic and smaller distances between ships, the course alterations alone are not always sufficient...
-
Chromatographic separation, determination and identification of ecdysteroids: Focus on Maral root (Rhaponticum carthamoides, Leuzea carthamoides )
PublikacjaThe review presents general principles for choosing optimal conditions for ecdysteroid separation, identification, and isolation using HPLC/TLC techniques in RP, NP- HILIC or NP modes. Analytics of ecdyteroids pose a still insufficiently resolved problem. Plant-derived ecdysteroids are a point of interest of pharmaceutical industry and sport medicine due to their postulated adaptogenic and anabolic properties. In insects, ecdysteroids...
-
Influence of separation gap on the response of colliding models of steel structures under seismic and paraseismic excitations
PublikacjaAs a result of high urbanization, the need to erect closely-spaced buildings forces designers to consider collisions between structures taking place during ground motions. Experimental and numerical studies have confirmed that such collisions (often referred to as structural pounding) may cause serious damage to the structural elements and even lead to total collapse of colliding structures. The main reason of earthquake-induced...
-
Towards large-scale application of nanoporous materials in membranes for separation of energy-relevant gas mixtures
PublikacjaMembranes containing nanoporous materials (such as zeolites, metal–organic materials and 2D materials such as graphene derivatives) may allow more efficient separation of gas mixtures relevant to emerging energy technologies. For example, such membranes could be applied in the separation of gases containing mixtures of carbon dioxide (CO2) and hydrogen (H2). However, these membranes are currently at a relatively low technology...
-
Effectiveness of toluene separation from gas phase using supported ammonium ionic liquid membrane
PublikacjaAmmonium ionic liquids (ILs) are relatively cheap in synthesis and environmentally benign and despite that they have been very rarely used in gas separation. In this research we used several ammonium ILs as liquid membranes for removal of residual toluene from gas phase. Ionic liquids used in this study were composed of bis(trifluoromethylsulfonyl)imide anion [Tf2N] and trimethylbutylammonium [N1114], trietylbutylammonium [N2224],...