Search results for: shallow water acoustics

Transdermal transport of collagen and hyaluronic acid using water in oil microemulsion

Publication

- INTERNATIONAL JOURNAL OF PHARMACEUTICS - Year 2019

Collagen and hyaluronic acid (HA) are biopolymers that affect the appearance and condition of the skin. Delivery of these compounds into the skin is highly challenging since have a number of disadvantageous properties, such as high molecular weight and hydrophilicity. Here, we evaluated the transdermal penetration of low and high molecular weight collagen and HA from microemulsions. A number of microemulsion formulations, differing...

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Structural Properties and Water Uptake of SrTi1−xFexO3−x/2−δ

Publication

- Materials - Year 2020

In this work, Fe-doped strontium titanate SrTi1−xFexO3−x/2−δ, for x = 0–1 (STFx), has been fabricated and studied. The structure and microstructure analysis showed that the Fe amount in SrTi1−xFexO3−x/2−δ has a great influence on the lattice parameter and microstructure, including the porosity and grain size. Oxygen nonstoichiometry studies performed by thermogravimetry at different atmospheres showed that the Fe-rich compositions...

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Transparent TiO2 nanotubes supporting silver sulfide for photoelectrochemical water splitting

Publication

W. Lipińska
S. Wolff
K. Dehm
S. Hager
J. Gumieniak
A. Kramek
R. Crisp
E. Coy
K. Grochowska
K. Siuzdak

- NANOSCALE - Year 2024

Differences between photoelectrochemical and electrochemical activity were thoroughly investigated for the oxygen evolution reaction mediated by Ag2S deposited on two types of ordered titania substrates. Titanium dioxide nanotubes were fabricated by anodization of magnetron sputtered Ti films on ITO-coated glass substrates or directly from Ti foil. Further, Ag2S deposition on the nanotubes was carried out using successive ionic...

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Effect of free water on the quasi‑static compression behavior of partially‑saturated concrete with a fully coupled DEM/CFD approach.

Publication

- GRANULAR MATTER - Year 2024

The work aims to numerically investigate the quasi-static response of partially fluid-saturated concrete under two-dimensional uniaxial compression at the mesoscale. We investigated how the impact of free pore fluid content (water and gas) affected the quasi-static strength of concrete. The totally and partially fluid-saturated concrete behavior was simulated using an improved pore-scale hydro-mechanical model based on DEM/CFD....

Dispersive Micro‐Solid Phase Extraction of Selected Metals in Water and Food Samples Followed by ICP‐OES Analysis: Method Development, Analysis of Real Samples and Greenness Evaluation

Publication

M. Sajid
M. Kabeer
M. K. Nazal
M. Younas
J. Płotka-Wasylka

- ChemistrySelect - Year 2024

Multiwalled carbon nanotubes (MWCNTs) are well-known adsorbents because of their high surface area, layered and hollow architecture, hydrophobicity, and multiple and easily accessible adsorption sites. In this study, MWCNTs were used for dispersive micro-solid-phase extraction of various metal chelates in environmental and food samples. Different parameters such as concentration of the chelating reagent, the sorbent dosage, the...

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Study of probe signal bandwidth influence on estimation of coherence bandwidth for underwater acoustic communication channel

Publication

- APPLIED ACOUSTICS - Year 2021

A signal transmitted in a shallow Underwater Acoustic Communication (UAC) channel suffers from time dispersion due to the multipath propagation and the refraction phenomena. This causes intersymbol interference of the received signal and frequency-selective fading observed in its spectrum. Coherence bandwidth is one of the key transmission parameters used for designing the physical layer of a data transmission system to minimise...

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Actual field corrosion rate of offshore structures in the Baltic Sea along depth profile from water surface to sea bed

Publication

J. Orlikowski
M. Szociński
K. Żakowski
P. Igliński
K. Domańska
K. Darowicki

- OCEAN ENGINEERING - Year 2022

The paper presents the results of field electrochemical investigations on the corrosion rate of carbon steel in seawater of the Baltic Sea at the location of the Baltic Beta production rig. The measurements were conducted throughout the year in seawater at different depths from the sea surface to the sea bed (about 75 m). The results revealed corrosion aggressiveness of the seawater along the entire depth profile. There was...

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Underwater acoustic communication system using broadband signal with hyperbolically modulated frequency

Publication

- Vibrations in Physical Systems - Year 2021

The implementation of reliable acoustic underwater communication in shallow waters is a scientific and engineering challenge, mainly due to the permanent occurrence of the multipath phenomenon. The article presents the concept of a transmission system using a broadband signal with hyperbolically modulated frequency (HFM) to transmit data symbols and synchronize data frames. The simulation tests were carried out in channels with...

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Performance of Coherent Modulation Scheme Used in Acoustic Underwater Communication System

Publication

- Vibrations in Physical Systems - Year 2019

The development of an acoustic underwater communication system for shallow waters is still a big scientificand construction challenge. Currently, non-coherent modulations in combination with strong channel coding are used to achieve reliable communication with low rate in such a channel. To obtain transmission with a higher transmission rate, it is required to use coherent modulation. This paper presents the assumptions of such...

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Solution of the dike-break problem using finite volume method and splitting technique

Publication

D. Gąsiorowski

- TASK Quarterly - Year 2011

In the paper the finite volume method (FVM) is presented for the solution of two-dimensional shallow water equations. These equations are frequently used to simulate the dam-break and dike-break induced flows. The applied numerical algorithm of FVM is based on the wave-propagation algorithm which ensures a stable solution and simultaneously minimizes the numerical errors. The dimensional decomposition according to the coordinate...

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Blended natural and synthetic coagulants for the COD and BOD removal from surface water; optimization by response surface methodology: The case of Gibe river

Publication

A. B. Bayu
Y. Endale
Z. A. Samuel
S. Kebede

- Heliyon - Year 2024

A novel wastewater treatment method is presented in this study. It combines natural coagulants derived from watermelon seeds with the commonly used synthetic coagulant alum. This research demonstrates a remarkable synergy between these two coagulants in removing nutrients from Gibe River wastewater. Combining natural and chemical coagulants often improves water treatment by enhancing particle destabilization, accelerating floc...

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Computational analysis of substituent effects on proton affinity and gas-phase basicity of TEMPO derivatives and their hydrogen bonding interactions with water molecules

Publication

A. Shiroudi
M. Śmiechowski
J. Czub
M. A. Abdel-Rahman

- Scientific Reports - Year 2024

The study investigates the molecular structure of 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) and its derivatives in the gas phase using B3LYP and M06-2X functional methods. Intermolecular interactions are analyzed using natural bond orbital (NBO) and atoms in molecules (AIM) techniques. NO2-substituted TEMPO displays high reactivity, less stability, and softer properties. The study reveals that the stability of TEMPO derivatives...

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Diver Observations by Means of Acoustic Methods

Publication

- ACTA PHYSICA POLONICA A - Year 2013

Searching for objects, especially small ones, moving under water near its the free surface, is always not an easy task. Designing tools for the detection of such targets is a real challenge when the possibility of a terrorist attack is a real threat. This paper presents some aspects of diver detection by means of acoustics methods, both active (side scan sonar) and passive ones (linear receiving antenna). This approach is quite...

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Chemometric estimation of natural water and sediment using toxicity tests and physicochemical parameters

Publication

A. Kuczyńska
L. Wolska
V. Simeonov
S. Tsakovski
S. Zahov
J. Namieśnik

- Journal of Balkan Ecology - Year 2006

Oceny jakości wód dokonano na podstawie analizy chemometrycznej bazy danych monitoringowych, składającej się z wyników testów toksyczności i wyników badań parametrów fizykochemicznych. Badaniom poddano próbki wód powierzchniowych pobrane z Jeziora Turawskiego oraz próbki wód podziemnych pobranych z otworów badawczych wykonanych w jego dnie, jak i wokół niego. Zastosowano następujące metody chemometryczne: analizę wiązkową i analizę...

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Problems of inland navigation in Poland in view of integrated water resources management (IWRM)

Publication

T. Jarzębińska

- Year 2007

W artykule przedstawiono zasady zintegrowane zarządzania gospodarką wodna. Przedstawiono rolę żeglugi środlądowej w gospodarce wodnej Polski i krajów czlonkowskich Unii Europejskiej. Przedstawiono aktualny stan dróg wodnych w Polsce, ograniczenia rozwoju i perspektywy na przyszłośc z punktu widzenia ZZGW.

Experimental research on effectiveness of the magnetic fluid seals for rotary shafts working in water

Publication

L. Matuszewski
Z. Szydło

- Polish Maritime Research - Year 2007

Uszczelnianie wałów obrotowych, łożysk i innych zespołów mechanicznych, za pomocą cieczy magnetycznej, tworzącej przegrodę uszczelniającą utrzymywaną siłami pola magnetycznego jest techniką uszczelniania, stosowaną z powodzeniem w urządzeniach pracujących w środowisku gazowym przy ciśnieniu do około 1,0 MPa. Uszczelnienia te umożliwiają również skuteczne rozwiązywanie problemu szczelności przepustów stałych i ruchowych w urządzeniach...

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Complexation of amino acids derivatives in water by calix[4]arene phosphonic acids

Publication

- Journal of Inclusion Phenomena and Macrocyclic Chemistry - Year 2008

Series of the calix[4]arene phosphonic acids with various substituents at the lower rim was synthesized. Complexing properties of these receptors towards methyl esters of six amino acids strongly depended on the calix[4]arene conformation flexibility. The complex formation processes were monitored using 1H NMR spectroscopy (deuterated phosphate buffer at pD 7.3, 22 oC) and association constant values were evaluated. Inherently...

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Environmentally friedly propeller shaft support with the use of water lubricated foil bearings

Publication

- POLISH JOURNAL OF ENVIRONMENTAL STUDIES - Year 2009

W pracy przedstawiono podsumowanie prowadzonych badań w celu opracowania oryginalnej metodyki projektowania oraz technologii wykonania pierwszego w świecie łożyska foliowego smarowanego wodą. Zaprezentowano koncepcje nowego łożyska foliowego poprzecznego oraz opisano opracowany algorytm obliczeniowy wykorzystany do predykcji jego charakterystyk. W rezultacie prowadzonych prac opracowano i przebadano doświadczalnie na stanowisku...

Removal of organic compounds from water by solvent sublation. Criteria for solvent selection.

Publication

- POLISH JOURNAL OF ENVIRONMENTAL STUDIES - Year 2009

Proces flotoekstrakcji zastosowano do usuwania z wody następujących związków organicznych: tetrachlorku węgla, chloroformu, 1,3,5-trimetylobenzenu (mezytylenu), fenolu i 2,4,5-trichlorofenolu. Jako odbierające fazy organiczne użyto: olej mineralny, 1-dekanol, 1-oktanol, octan amylu, dodekan i tetradekan. Mechanizmem decydującym o usuwaniu lotnych związków organicznych (VOC) było odparowanie do wnętrza pęcherzyków gazu, podczas...

Possible application of new class of solvents in the purification of water used in hydraulic fracturing

Publication

Z. Lustig

- Year 2012

Nowym źródłem energii niekonwencjonalnej w Polsce może być gaz, który jest uwięziony w łupkach. Podczas poszukiwań gazu łupkowego, duże ilości wody wykorzystywanej w procesie szczelinowania hydraulicznego powracają na powierzchnię zanieczyszczone. Istnieje wiele metod usuwania śladowych ilości węglowodorów tj. fizyczne czyli filtracja czy chemiczne czyli zakwaszanie, ale mogą one być nieskuteczne. Pożądana metoda to monitorowanie...

Investigation of the distribution of imidazolium ionic liquids in the environment - aggregation in water and sorption on minerals

Publication

- Year 2011

Wpływ cieczy jonowych na środowisko, a w szczególności: migracja do wód powierzchniowych i gruntowych, jak również transport/retencja w gruntach jest determinowany przede wszystkim przez właściwości fizykochemiczne cieczy jonowej jak i właściwości matrycy środowiskowej. Znajomość zjawisk zachodzących w wyniku kontaktu cieczy jonowych z wodą oraz glebą jest jednym z podstawowych warunków oceny ryzyka chemicznego. W pracy wykazano,...

The calculation long-term physical field created by water flow around the ship

Publication

J. Bielański

- HYDROACOUSTICS - Year 2010

The paper presents a description of the problems with fluid flow around a ship. Using the described solution of the problem were performed numerical calculations using the boundary element method. Were also presented preliminary results of the calculation of pressure fields at the bottom of the ship, taking into account the impact of the bottom.

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Multistatic sonar for man-made lakes and water-power plants antiterrroristic protection

Publication

- Year 2010

Artykuł opisuje nową koncepcję dopplerowskiego sonaru multistatycznego opracowanego w Katedrze Systemów Elektroniki Morskiej Politechniki Gdańskiej. System składa się z sieci hydrofonów rozmieszczonych równomiernie w obserwowanym akwenie oraz ze źródła dźwięku w postaci fali ciągłej o stałej częstotliwości i bardzo niskim natężeniu. Dzięki zastosowaniu specjalnie opracowanych algorytmów przetwarzania sygnałów uzyskuje się poprawną...

Ni-MOF-based electrodes: A promising strategy for efficient overall water splitting

Publication

A. Dymerska
B. Środa
B. Zielińska
E. Mijowska

- Electrochimica Acta - Year 2023

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Analysis of energy and economic efficiency of water heating system powered by photovoltaic module

Publication

N. Kozłowska
W. Kruszelnicka
A. Mroziński

- Mechanik - Year 2015

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Higher harmonics of converter currents in energy conversion system of small water plants

Publication

T. Sobczyk
W. Mazgaj
Z. Szular
T. Wegiel

- Year 2011

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Operating and economical conditions of cooling water control for marine steam turbines condensers

Publication

A. Błaszczyk
J. Głuch
A. Gardzilewicz

- Polish Maritime Research - Year 2011

W pracy dokonano analizy ekonomicznej i eksploatacyjnej sterowania pracą pomp wody chłodzącej skraplacze turbin okrętowych. Wzięto pod uwagę cechy konstrukcyjne pomp wody chłodzącej skraplacze główne i najnowsze wyniki badań dla takich pomp w zastosowaniach lądowych. Uwagę skupiono przede wszystkim na turbinowych parowych siłowniach okrętowych.

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