Search
Filters
total: 1931
filtered: 1526
displaying 1000 best results Help
Search results for: cold-formed section
-
Experimental investigation of heat transfer enhancement in straight and U-bend double-pipe heat exchanger with wire insert
PublicationIn this paper, the possibility of heat transfer enhancement in the U-bend exchanger was presented. Experimental research has been carried out for four individual heat exchanger constructions i.e. plain tube in tube, turbulized tube in tube, plain U-bend and U-bend with turbulator. Also, heat transfer experiments for various boundary conditions were performed to obtain reference values. In case of U-bend exchanger with and without...
-
Vibrational Quenching of Optically Pumped Carbon Dimer Anions
PublicationCareful control of quantum states is a gateway to research in many areas of science such as quantum information, quantum-controlled chemistry, and astrophysical processes. Precise optical control of molecular ions remains a challenge due to the scarcity of suitable level schemes, and direct laser cooling has not yet been achieved for either positive or negative molecular ions. Using a cryogenic wire trap, we show how the internal...
-
In Silico Safety Assessment of Bacillus Isolated from Polish Bee Pollen and Bee Bread as Novel Probiotic Candidates
PublicationBacillus species isolated from Polish bee pollen (BP) and bee bread (BB) were characterized for in silico probiotic and safety attributes. A probiogenomics approach was used, and in-depth genomic analysis was performed using a wide array of bioinformatics tools to investigate the presence of virulence and antibiotic resistance properties, mobile genetic elements, and secondary metabolites. Functional annotation and Carbohydrate-Active...
-
The influence of Nigella sativa essential oil on proliferation, activation, and apoptosis of human T lymphocytes in vitro
PublicationIn previous work, we tested the immunomodulatory effect of Nigella sativa (NS) fatty oil. Our results demonstrated that unrefined, obtained by cold pressing black cumin seed oil inhibited lymphocytes’ proliferation and induced their apoptosis in a dose-dependent manner. In this study, we examined the immunomodulatory properties of essential oil (EO) obtained from the NS seeds by hydrodistillation and its two main constituents:...
-
Protection and viability of fruit seeds oils by nanostructured lipid carrier (NLC) nanosuspensions
PublicationIn this paper, we focused on the development of nanostructured lipid carriers (NLCs) for dermal application. The NLC matrix was designed as a protective reservoir of biological active compounds that naturally occur in domestic fruit seed oils. Over the years, emulsions, as a popular physicochemical form of personal care products, were refined in order to obtain the best possible penetration into the skin of any bioactive compound...
-
Novel two-step synthesis method of thin film heterojunction of BiOBr/Bi2WO6 with improved visible-light-driven photocatalytic activity
PublicationA novel two-step ionic liquid assisted procedure was applied for a controllable synthesis of BiOBr/Bi2WO6 heterojunction thin films. The preparation route involved an anodic oxidation of tungsten foil and hydrothermal transformation of as-anodized oxide in the presence of bismuth precursor and ionic liquid, N-butylpyridinium bromide [BPy][Br]. The BiOBr plates with irregular shapes adhered to the surface of flower-like Bi2WO6 and...
-
A Subspace-Splitting Moment-Matching Model-Order Reduction Technique for Fast Wideband FEM Simulations of Microwave Structures
PublicationThis article describes a novel model-order reduction (MOR) approach for efficient wide frequency band finite-element method (FEM) simulations of microwave components. It relies on the splitting of the system transfer function into two components: a singular one that accounts for the in-band system poles and a regular part that has no in-band poles. In order to perform this splitting during the reduction process, the projection...
-
Effectiveness of toluene separation from gas phase using supported ammonium ionic liquid membrane
PublicationAmmonium 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],...
-
The effect of morphology and crystalline structure of Mo/MoO3 layers on photocatalytic degradation of water organic pollutants
PublicationMolybdenum oxide layers were formed by anodization of the Mo metallic foil in a water/ethylene glycol-based electrolyte containing fluoride ions. The as-prepared, amorphous samples were annealed in air at different temperatures in a range from 100 �C to 700 �C. The crystal phase and morphology of anodized and annealed MoO3 layers were investigated using X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. The...
-
Manganese Phosphatizing Coatings: The Effects of Preparation Conditions on Surface Properties
PublicationManganese phosphate coating could be used to protect the surface of steel products. However, it is essential to determine the effects which process parameters, as well as the types of additives used, have on the efficiency of coating deposition. Thus, we present here a process of phosphatization of low-alloy steel (for 15 min at 95 ◦C) in manganese/nickel baths followed by a passivation process with the use of a silicon and zircon...
-
Sources and Fate of PAHs and PCBs in the Marine Environment
PublicationThe assessment of a hazard resulting from the pollution of the environment by chemical compounds is in principle limited to the determination of their concentrations in its various compartments. But for solving many problems in this context, knowledge of the emission sources, transport pathways, and sites of deposition is of great benefit. By far the largest amounts of pollutants, regardless of where they were discharged, end up...
-
The effect of ionic liquids on the surface and photocatalytic properties of semiconducting materials
PublicationSemiconductor-mediated photocatalysis represents an environmentally friendly technology that could be used for the degradation of different pollutants in the gas and aqueous phases, for hydrogen generation, and for CO2-to-valuable product transformation reactions. Therefore, it is extremely important to accurately design a photocatalyst with the relevant features. In recent years, ionic liquids have often been employed as reagents...
-
Development of Microstructured Carbon Coatings by Substrate-Catalytic CVD
PublicationCarbon nanostructured films were synthesized by chemical vapor deposition (CVD) on H18 stainless steel (AISI 440C) sheets with an H2/CH4/N2 gas mixture at various substrate temperatures. During the synthesis, the iron and chromium oxide layer was formed between the steel and carbonaceous layer. The carbon films exhibited wall-like and spherical morphologies and structures, as characterized by scanning electron microscopy and Raman...
-
Environmental Fate of Two Psychiatric Drugs, Diazepam and Sertraline: Phototransformation and Investigation of their Photoproducts in Natural Waters
PublicationExperimental studies were conducted to investigate the photodegradation of diazepam and sertraline, two of the most frequently used psychiatric drugs, induced by xenon lamp irradiation, which overlap the sunlight spectra, and natural sunlight. Degradation kinetics was established indicating the occurrence of autocatalytic reactions. The application of liquid chromatography coupled to quadrupole time-of-flight mass spectrometry...
-
Multimedia interface using head movements tracking
PublicationThe presented solution supports innovative ways of manipulating computer multimedia content, such as: static images, videos and music clips and others that can be browsed subsequently. The system requires a standard web camera that captures images of the user face. The core of the system is formed by a head movement analyzing algorithm that finds a user face and tracks head movements in real time. Head movements are tracked with...
-
Unraveling a novel microwave strategy to fabricate exposed {001}/{101} facets anatase nanocrystals: Potential for use to the elimination of environmentally toxic metronidazole waste
PublicationThis study present a novel microwave strategy to fabricate highly active anatase particles, exposing {101} and {001} facets. Microwave treatment time was shown to determine the growth of crystals in a certain direction. To the best of our knowledge, it is the first report revealing that the contact time of TiO2 crystals with fluorine ions during the microwave process affects the formed morphology, in particular exposed facets ratio....
-
Precipitation of calcium carbonate in the presence of rhamnolipids in alginate hydrogels as a model of biomineralization
PublicationThis paper reports the effects of rhamnolipids presence in the alginate hydrogel and CO32- solution, on the precipitation of CaCO3 in the Ca2+ loaded alginate hydrogel. Characteristics of the formed particles are discussed. Model conditions containing alginate hydrogel and rhamnolipids were used in order to mimic the natural environment of biomineralization in biofilms. It has been shown that rhamnolipids affect the characteristics...
-
Activation of the C=P bond in phosphanylphosphaalkenes C=P–P bond system) in the reaction with nucleophilic reagents: MeLi, nBuLi and tBuLi
PublicationThree reactions of phosphanylphosphaalkene (1) with nucleophiles were performed to activate the diphosphorus monomer. We observed similar results in the reactions with MeLi and nBuLi, in which the P–P bond is cleavaged and triphosphorus systems [P(Me)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1a'') and [P(nBu)2–CH(biph)–CH(biph)–P–(PtBu 2)]- (1b''), respectively, are formed depending on the nucleophilic reagent (biph ¼ biphenyl). In the...
-
A survey of strategies for communication networks to protect against large-scale natural disasters
PublicationRecent natural disasters have revealed that emergency networks presently cannot disseminate the necessary disaster information, making it difficult to deploy and coordinate relief operations. These disasters have reinforced the knowledge that telecommunication networks constitute a critical infrastructure of our society, and the urgency in establishing protection mechanisms against disaster-based disruptions. Hence, it is important...
-
Longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices
PublicationThis paper presents investigations of longitudinally magnetized left-handed cylindrical ferrite coupled line junction for nonreciprocal devices. The proposed junction is formed as a quasi periodic arrangement of N unit cells. Each unit cell is realized as a cascade of short cylindrical ferrite coupled lines with reactance circuit composed of series capacitors and parallel inductors. The left-handed cylindrical junction with π/4...
-
Targ Węglowy as the keystone of two ring road complexes of Gdańsk city centre
PublicationThe urban structure of Gdansk city centre is determined by two ring road complexes. The first of them, the Gdansk Ring, has been created as a result of a city defortification at the turn of the 19th and 20th centuries and has been destroyed in the end of World War Two with the rest of Gdansk. The second, the Main Town Green Belt, has been formed in place of the medieval fortification system of the city’s most important historical...
-
Tinnitus Therapy Based on High-Frequency Linearization Principles - Preliminary Results
PublicationThe aim of this work is to present problems related to tinnitus symptoms, its pathogenesis, hypotheses on tinnitus causes, and therapy treatment to reduce or mask the phantom noise. In addition, the hypothesis on the existence of parasitic quantization that accompanies hearing loss has been recalled. Moreover, the paper describes a study carried out by the Authors with the application of high-frequency dither having specially formed...
-
Syntheses and structures of the first terminal phosphanylphosphido complex of hafnium [cp2hf(cl){η1-(me3si)p-p(net2)2}] and the firstzirconocene-phosphanylphosphinidene dimer [cp2zr{μ2-p-p(net2)2}2zrcp2]
PublicationReactions of (Et2N)2P-P(SiMe3)Li with [Cp2MCl2] (M= Zr, Hf) in toluene or pentane yield the related terminal phosphanylphosphido complexes [Cp2M(Cl){η1-(Me3Si)P-P(NEt2)2}]. The solid statestructure of [Cp2Hf(Cl){η1-(Me3Si)P-P(NEt2)2}] was established by single crystal X-ray diffraction. The reaction of (Et2N)2P-P(SiMe3)Li with [Cp2ZrCl2] in THF or DME solutions leads to the formationof deep red crystals of the first neutral diamagnetic...
-
"Raport z wstępnych badań własności stali trudnościeralnej 460HB",. ang "Report on preliminary tests of the properties of wear-resistant steel 460HB"
PublicationMikrostrukturę badanej stali trudnościeralnej 460HB stanowi drobnoziarnisty martenzyt odpuszczony, który jest właściwy dla stali konstrukcyjnych niskowęglowych, niskostopowych ulepszonych cieplnie. W przypadku blach grubych, do których zalicza się badana stal, struktura może ulec zaburzeniu, jeżeli w hutniczym procesie wytwórczym wystąpiła niejednorodność odkształcenia plastycznego i w konsekwencji tworzenie się pasm segregacyjnych,...
-
ANALIZA PRZEPUSTOWOŚCI WYBRANEGO UKŁADU TOROWEGO W PRZESTRZENI CZĘŚCIOWO – UPORZĄDKOWANEJ
PublicationNa sieci kolejowej istotny wpływ na płynność ruchu mają odpowiednio usytuowane odcinki odstępowe. Z podobną sytuacją mamy do czynienia przy modernizacji stacji kolejowych i tworzeniu nowych rozwiązań, w których należy uwzględnić prognozy rozwoju ruchu na danym elemencie sieci kolejowej. Jednak w przypadku stacji sytuacja staje się dużo bardziej skomplikowana i kosztowna, gdyż poprawa przepustowości wymaga istotnych zmian organizacyjnych...
-
STRATEGIA DOBORU PROCESU PRODUKCYJNEGO WG. REAKCJI NA ZAMÓWIENIA KLIENTA
PublicationW opracowaniu poruszono zagadnienie doboru strategii wytwarzania w zakresie procesu produkcyjnego. W ramach tego zagadnienia dokonano podziału procesów produkcyjnych wg różnych kryteriów. Skupiano się na podziale procesów wg. reakcji na zamówienia klienta. Przedstawiono pokrótce najistotniejsze cechy charakteryzujące tego typu procesy. By móc określić strategię w zakresie procesu produkcyjnego zestawiono kryteria wyboru procesu...
-
Pomiarowa ocena efektywności systemu antyspoofingowego opartego na przetwarzaniu wieloantenowym
PublicationNiniejszy referat dotyczy problemu wykrywania i przeciwdziałania atakom typu spoofing w globalnych systemach nawigacji satelitarnej. Pierwsza część referatu stanowi wprowadzenie w temat spoofingu oraz przegląd sposobów jemu przeciwdziałania. Następnie, przedstawiono autorską koncepcję systemu antyspoofingowego opartego na przetwarzaniu wieloantenowym, a także opisano implementację prototypu tego systemu. Część trzecią poświęcono...
-
Electron scattering from tin tetrachloride (SnCl4) molecules
PublicationAbsolute grand-total cross section (TCS) for electron scattering from a tin tetrachloride, SnCl4, molecule was measured at electron-impact energies ranging from 0.6 to 300 eV, in the linear electron-transmission experiment. The measured TCS energy dependence shows two very pronounced enhancements peaking near 1.2 eV and around 9.5 eV, separated with a deep minimum centered close to 3 eV. The low energy structure is attributed to...
-
Sound engineering as our commitment to its creators in Poland
PublicationSound engineering is an interdisciplinary and rapidly expanding domain. It covers many aspects, such as sound perception, studio and sound mastering technology, music information retrieval including content-based search systems and automatic music transcription frameworks, sound synthesis, sound restoration, electroacoustics, and other ones constituting multimedia technology. Moreover, machine learning methods applied to the topics...
-
Debonding Detection in Reinforced Concrete Beams with the Use of Guided Wave Propagation
PublicationOne of the most frequent damage of the reinforced concrete structures is debonding between steel bar and concrete cover. In the case of debonding occurrence not only the strength of the structure decreases, but also it is more vulnerable to corrosion damages. For this reason fast and effective methods of debonding detection in an early stage of its development need a significant boost. The paper presents analytical and experimental...
-
Resonances and Dissociative Electron Attachment in HNCO
PublicationIn a combined experimental and theoretical study, we probe the dissociative electron attachment in isocyanic acid HNCO. The experimental absolute cross section for the NCO− fragment shows a sharp onset and fine structures near the threshold. The autoionizing state responsible for the dissociative attachment is found in both the R-matrix calculation and using analytic continuation in the coupling constant. The involved A' resonance...
-
Security of export transactions in the offer of leading banks on the Polish market
PublicationThe following article presents the so-called conditioned payment methods, i.e. instruments for securing export transactions, such as letter of credit, documentary collection, bank guarantees, factoring and forfaiting. The characteristics of each particular method are presented as well as the transactions using them are described. In the following paper, the author included also the leading Polish banks, which offer the above- mentioned...
-
Vibration-Based Investigation of a Historic Bell Tower to Understand the Occurrence of Damage
PublicationABSTRACT The paper presents a survey of the historic Arch-cathedral bell tower in Vilnius induced by the appearance of cracks in the structure after a new bell system installation. An attempt is undertaken to identify the reason for the crack occurrence and to check a possible crack influence on global structural behaviour. The research is based on dynamic measurements made in the tower during ambient vibrations and during vibrations...
-
60 GHz Microstrip Van Atta Arrays for Millimeter Wave Identification and Localization
PublicationIn this paper performance comparison of co-polarized and cross-polarized microstrip Van Atta arrays working in the 60 GHz frequency range is presented. They can be treated as simple chipless RFID tags with frequency response based identification. Tags with three different nominal resonance frequencies of 57, 62 and 67 GHz are designed by scaling optimized base model. Designed 62 GHz co-polarized and cross-polarized arrays with...
-
Compact Dual-Polarized Corrugated Horn Antenna for Satellite Communications
PublicationIn this paper, a structure and design procedure of a novel compact dual-polarized corrugated horn antenna with high gain and a stable phase center for satellite communication is presented. The antenna incorporates an Ortho-Mode Transducer (OMT), a mode converter, and a corrugated structure. The compact OMT section is designed to be fed by standard WR-75 waveguides. The proposed compact design utilizes only ten corrugated slots...
-
Influence of nonlinearities on the efficiency and accuracy of FEM calculations on the example of a steel build-up thin-walled column
PublicationDue to the increase of computing capabilities of standard processing units, it is possible to perform complex analyses, considering a number of nonlinearities, such as geometric, material and boundary (contact) even on personal computers. In the paper, the authors have analysed the efficiency and accuracy of standard PC’s FEM calculations performed in Abaqus CAE 2017 software on the example of a critical load assessment of a thin-walled...
-
Electron collisions with cyanoacetylene HC3N : Vibrational excitation and dissociative electron attachment
PublicationWe experimentally probe electron collisions with HC3N in the energy range from 0 to 10 eV with the focus on vibrational excitation and dissociative electron attachment. The vibrational excitation cross sections show a number of resonances which are mode specific: the two dominant π∗ resonances are visible in the excitation of all the vibrational modes; however, broad σ ∗ resonances are visible only in certain bond-stretching vibrational...
-
Study of railway traffic safety based on the railway track condition monitoring system
PublicationThe solution to the problem of monitoring the railway track, as well as potentially dangerous objects and phenomena in the adjacent territories, is determined by the need to implement increased requirements for traffic safety (primarily to the geometric parameters of the devices of a long railway track under construction and functioning load-bearing highways), prevention of technological disasters and large-scale negative effects...
-
Numerical Modelling of Forced Convection of Nanofluids in Smooth, Round Tubes: A Review
PublicationA comprehensive review of published works dealing with numerical modelling of forced convection heat transfer and hydrodynamics of nanofluids is presented. Due to the extensive literature, the review is limited to straight, smooth, circular tubes, as this is the basic geometry in shell-and-tube exchangers. Works on numerical modelling of forced convection in tubes are presented chronologically in the first part of the article....
-
Application of Spinel and Hexagonal Ferrites in Heterogeneous Photocatalysis
PublicationSemiconducting materials display unique features that enable their use in a variety of applications, including self-cleaning surfaces, water purification systems, hydrogen generation, solar energy conversion, etc. However, one of the major issues is separation of the used materials from the process suspension. Therefore, chemical compounds with magnetic properties have been proposed as crucial components of photocatalytic composites,...
-
Experimental bases for the rail track surface damage detection system
PublicationA diagnosis of rail surface is generally based on the classical method of direct assessment and track geometry measurements. Identification and qualification of inequality and damage on the surface rails is depend on the skills and experience person who conducting inspection. In times of increasing exploitation of railways, infrastructure managers decide to use systems supporting the assessment of technical condition of the railways....
-
Technical diagnostics and monitoring of traction current collectors
PublicationNew evaluation methods of the technical condition of rolling stock current collectors are proposed in this paper. The method of automatic measurement of the pantograph static force characteristic, realized when the vehicle runs through the test section of the track with especially prepared overhead line height distribution, has been practically implemented by the Polish Railways. The method of testing the slipper spring suspension...
-
Analysis of the Environmental Impact of the Hull Construction of a Small Vessel Based on LCA
PublicationIn recent years, issues related to the impact of human activity on the natural environment have become pressing, and the challenge of global warming necessitates immediate action. To support environmental protection efforts, it has become imperative to adopt a broader perspective when evaluating various products and systems. A valuable tool for such assessments is a life cycle assessment (LCA), which enables a comprehensive analysis...
-
A semiempirical model for low energy electron–atom transport cross sections: The case of noble gases
PublicationA semiempirical approach to describe low energy electron–atom transport cross sections of easy implementation and reproduction is presented. The heart of the model is an energy independent two-parameter potential that was adjusted to reproduce the accurate total cross sections for He, Ne, Ar and Kr, measured with a threshold photoelectron source technique from meV up to 20 eV. Once the potential was conceived, the model was validated...
-
Application of Least Squares with Conditional Equations Method for Railway Track Inventory Using GNSS Observations
PublicationSatellite geodetic networks are commonly used in surveying tasks, but they can also be used in mobile surveys. Mobile satellite surveys can be used for trackage inventory, diagnostics and design. The combination of modern technological solutions with the adaptation of research methods known in other fields of science offers an opportunity to acquire highly accurate solutions for railway track inventory. This article presents the...
-
Thermal and economic investigation of straight and U-bend double tube heat exchanger with coiled wire turbulator
PublicationExperimental research has been carried out for four individual heat exchanger constructions, i.e., plain double tube, turbulized double tube, plain U-bend and U-bend with turbulator. Tests were made for the water-water system. The study covered a wide measuring range, i.e., Re = 800–9000 – on the shell side, for a constant cold water temperature of 9 ◦C and hot water of 50 ◦C. The heat exchangers were made from copper tubes with...
-
Novel single-stranded DNA-binding protein from psyvhrophilic bacterium Psychrobacter arcticus
PublicationTo study the biochemical properties of SSB from Psychrobacter arcticus (ParSSB), we have cloned the ssb genes obtained by PCR and have developed Escherichia coli overexpression systems. The gene consists of an open reading frame of 642 nucleotides encoding SSB protein of 213 amino acids with a calculated molecular mass of 22.8 kDa. The amino-acid sequence of ParSSB exhibits 49% identity and 57% similarity to Escherichia coli SSB....
-
A new B-D-galactosidase with a low temperature optimum isolated from the Antarctic Arthrobacter sp. 20B: gene cloning, purification and characterization.
PublicationA psychrotrophic bacterium producing a coldadaptedB-galactosidase upon growth at low temperatureswas classiWed as Arthrobacter sp. 20B. A genomic DNAlibrary of strain 20B introduced into Escherichia coliTOP10F' and screening on X-Gal (5-bromo-4-chloro-3-indolyl-B-D-galactopyranoside)-containing agar plates ledto the isolation of B-galactosidase gene. The B-galactosidasegene (bgaS) encoding a protein of 1,053 amino acids,with a...
-
Mercury content in beetroot and beetroot-based dietary supplements
PublicationTotal mercury (THg) concentrations in fifty-four beetroot-based DSs and seven lots of conventional and organic beetroots (divided into unpeeled, peeled, and skins) were determined by direct thermal decomposition-gold amalgamation cold vapour atomic absorption spectrometry. The analytical procedure was optimised and validated. The recovery (%) for Hg was 101.9 and 92.73 in BCR-463 and DOLT 4, respectively. The intermediate precision...
-
Effect of surface roughness on thermal-hydraulic characteristics of plate heat exchanger
PublicationIn the paper the experimental analysis of passive heat transfer intensification in the case of modeled plate heat exchanger is conducted. The plate heat exchanger is chosen for the analysis because this kind of heat exchangers could be prospectively applied in the ORC systems, however other areas or application are equally possible. The experimental setup was assembled at the Department of Energy and Industrial Apparatus of Gdansk...