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1

Impact of Sulfate in the Sand on the Absorption and Density of Metakaolin-Based Geopolymer Mortar

Thamer Sara Yahya, Al-Jaberi Layth Abdulbari

Journal of Ecological Engineering

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2023

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Vol. 24, nr 1

328--335

EN

The advancement of cement alternatives in the construction materials field is fundamental to sustainable development. Geopolymer is the optimal substitute for ordinary portland cement, which produces 80% less CO2 emissions. Metakaolin was used as one of the raw materials in the geopolymerization process. This research examined the influence of three different percentages of sulfate (0.00038, 1.532, and 16.24)% in sand per molarity of NaOH on the absorption and density of metakaolin-based geopolymer mortar (MK-GPM). Samples were prepared with two different molarities (8M and 12M) and cured at room temperature. The best results obtained for geopolymer mortar in the absorption and density test were (3.89%) and (2280 kg/m3), respectively, recorded with 12M with the lowest sulfate content (0.00038%) at 90 days. Moreover, it has been observed that the absorption percentage increased along with sulfate content in the sand, and an inverse relationship was recorded between the increasing sulfate percentages in the sand and density values of (MK-GPM).

2

Geopolymer Concrete Production by Using Nano-Bauxite Binder

Salman Sadeq Dawood, Jubier Najwa J., Al-Zubaidi Aseel B.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 10

305--314

EN

Iraqi bauxite ore was used in the manufacturing of geopolymer mortar and concrete. To de-hydroxylate and turn bauxite into an amorphous phase, it was heated to 650 degrees Celsius. Mixing bauxite nanoparticles with an active alkaline solution produces a geopolymer of high grade due to their high efficiency. The nano-bauxite geopolymer mortar is produced following ASTM C109 with various quantities of alkaline solution with molarity (8, 10, 12, and 14). At 3, 7, and 28 days, the maximum compressive strength of mortar with a molarity of 12 was 20.2, 49.7, and 65.3 MPa, respectively. The same quantity of molarity for the mortar was utilized for the production of geopolymer concrete using an alkaline solution. The weight of nano bauxite was substituted for the percentage of nano-glass and carbon nano-tubes that were included in the geopolymer concrete. This resulted in the utilization of nano-glass and carbon nano-tubes, the best ratios are 8% silica merge with 0.01% of carbon nano-tubes. At the age of 28 days, the water absorbency value was found to be 1.78%, and it was noted that the increased compressive strength reached 81.4 MPa. For the polymerization and performance hardening of samples at low temperatures (20±3 °C), geopolymers with nano-bauxite binders were manufactured without heat treatment. The increased compressive strength as well as resistance to freezing and thawing tests are a result of the superior performance and high requirements of nano-materials. XRD examination was performed, many geopolymer phases were generated, and the bond structures between alumina and silica were observed; these results confirm the development of geopolymer.

3

Design of Artificial Neural Network for Prediction of Hydrogen Sulfide and Carbon Dioxide Concentrations in a Natural Gas Sweetening Plant

Alardhi Saja Mohsen, Al-Jadir Thaer, Hasan Ahmed Mudheher, Jaber Alaa Abdulhady, Al Saedi Laith Majeed

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 2

55--66

EN

Gas sweetening is a fundamental step in gas treatment processes for environmental and safety concerns. One of the most extensively used and largely recognized solvents for gas sweetening is methyl diethanolamine (MDEA). One of the most crucial metrics for measuring the effectiveness of gas treatment units is the amount of acid gas that has been treated with MDEA solution. As a result, it should be regularly monitored to avoid operational issues in downstream processes and excessive energy consumption. In this study, the artificial neural network (ANN) approach was followed to predict the H2S and CO2 sour gases concentrations of sweetening process. The model was built using dataset gathered from a real operation plant in Iraq, collected from February 2019 to February 2020, and used as input to the neural network. The data include H2S and CO2 concentrations of the feed gas, temperature, pressure, and flow rate of the unit. The designed ANN model showed good accuracy in modeling the process under investigation, even for a wide range of parameter variability. The testing outcomes demonstrated a high coefficient of determination (R2) of greater than 0.99, while the overall training performance showed a low mean squared error (MSE) of less than 0.0003.

4

Organiczne diody elektroluminescencyjne na bazie pochodnych pirazolochinoksalin

Pokladko-Kowar Monika, Wojtasik Katarzyna

Przegląd Elektrotechniczny

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2022

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R. 98, nr 9

220--223

PL

Pochodne pirazolochinoksalin (A-PQX) badano pod kątem zastosowań w organicznych diodach elektroluminescencyjnych (OLED). Wykonane zostały pomiary widm absorpcyjnych, fotoluminescencyjnych oraz elektroluminescencyjnych. Zbudowane zostały jednowarstwowe komórki o strukturze ITO/PEDOT:PSS/PVK+A-PQX/Ca/Al. Wyznaczone zostały parametry charakterystyczne dla OLED. Maksymalna luminescencja otrzymana dla tych struktur wynosiła 884 cd/m2 dla diody na bazie 7-N,N-dietylo-1-fenylo-3-metylo-1H-pirazolo[3,4-b]chinoksaliny (7- PQX).

EN

Pyrazoloquinoxaline derivatives (A-PQX) have been studied for applications in organic light emitting diodes (OLEDs). Single-layer OLEDs with the structure: ITO/PEDOT:PSS/PVK+A-PQX/Ca/Al were built. Parameters characteristic for OLED were determined. The absorption, photoluminescent and electroluminescent spectra were measured. The maximum luminescence obtained for these structures was 884 cd/m2 for a diode based on 7-N,N-diethyl-3-methyl-1-phenyl-1H-pyrazolo[3,4-b]quinoxaline (7A-PQX).

5

Light absorption of a polymer based single/multi junction solar cell model

Varghese Jeremiah S., Ruhneb Benhur, Moni D. Jacquline, Du John Victor H.

Przegląd Elektrotechniczny

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2022

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R. 98, nr 1

19--22

EN

In this paper, a detailed study and simulation modelling on light absorption using PDMS material in a single/multi-junction solar cells is carried out. Since PDMS material is a good absorber of light, it is used as an active layer of a solar cell. We choose PDMS because its properties, mainly exceptional intrinsic stability against thermal and ultraviolet light, induced good mechanical properties and stress over a wide range of temperatures. Good transmittance due to the absence of UV absorbers is one of its best characteristics. With the help of the transfer matrix method, which is used for optical modeling of an organic solar cell, inspired by the McGehee Group in Stanford University. The result and simulation is done using MATLAB and in the end we are going to draw a conclusion about the ideal materials that a good solar cell has to have to have good absorption.

PL

W niniejszym artykule przeprowadzono szczegółowe badania i modelowanie symulacyjne absorpcji światła przy użyciu materiału PDMS w jedno-/wielozłączowych ogniwach słonecznych. Ponieważ materiał PDMS jest dobrym pochłaniaczem światła, jest używany jako aktywna warstwa ogniwa słonecznego. Wybieramy PDMS, ponieważ jego właściwości, głównie wyjątkowa stabilność wewnętrzna w stosunku do światła termicznego i ultrafioletowego, indukowały dobre właściwości mechaniczne i naprężenia w szerokim zakresie temperatur. Dobra przepuszczalność ze względu na brak absorberów UV jest jedną z jego najlepszych cech. Za pomocą metody przeniesienia macierzy, która służy do optycznego modelowania organicznego ogniwa słonecznego, inspirowanej przez Grupę McGehee na Uniwersytecie Stanforda. Wynik i symulację wykonano przy użyciu MATLAB, a na koniec wyciągniemy wniosek na temat idealnych materiałów, które dobre ogniwo słoneczne musi mieć dobrą absorpcję.

6

Fabrication and amplified spontaneous emission behavior of FAPbBr3 perovskite quantum dots in solid polymer rods

Khan M. Naziruddin, Almohammedi Abdullah

Materials Science Poland

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2022

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Vol. 40, No. 1

84--100

EN

Formamidinium lead tribromide (FAPbBr3) perovskite quantum dot (PQ-Dot) solution was incorporated in a polymer sol, which was used to fabricate solid nanocomposite rods and disks. The solid nanocomposite samples were studied by different characterization techniques. The absorption, emission, and excitation spectra of the PQ-Dot in the solid rods/disks were quite significant as compared to the spectra of the PQ-Dot solution. Scanning electron microscopy (SEM) was used to inspect the structural morphology of the PQ-Dot in the solid environment. The PQ-Dot particles were evidently present in the solid matrix and were confirmed by the SEM images and energy dispersive X-ray spectroscopy (EDX) spectra. The size of the PQ-Dots was examined by transmission electron microscopy (TEM). The majority of the particles were about 3–8 nm in size. The spontaneous and stimulated emission profiles of the solid composite rods/disks were studied using pumping energy ranging from 2 μJ to 18 μJ from a high-power picosecond neodymium-doped yttrium aluminum garnet (Nd:YAG) tunable laser system. The observed emission signal was quite significant. The emission peak of the PQ-Dot solution had a slight change when it was included in the solid matrix. Amplified spontaneous emission (ASE) behavior was obtained from the PQ-Dot composite rod. The ASE peaks were quite steady at different levels of excitation energy. ASE was achieved at low threshold energy. The composite rod with ASE behavior indicates that it is a promising composite material that can be used to achieve lasing in the future. The ASE obtained from the composite rods/disks may improve to achieve lasing if a high concentration of PQ-Dot solution is used in the matrix.

7

Application of a Gas Sensor Array to Effectiveness Monitoring of Air Contaminated with Toluene Vapors Absorption Process

Dobrzyniewski Dominik, Szulczyński Bartosz, Gębicki Jacek

Journal of Ecological Engineering

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2022

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Vol. 23, nr 10

269--282

EN

This article demonstrates the application of a gas sensor array to monitor the effectiveness of the absorption process of air stream purification from odorous compounds (toluene vapors). A self-constructed matrix consisting of five commercially available gas sensors was used. Multiple linear regression (MLR) was selected as the statistical technique used to calibrate the matrice. Gas chromatography coupled with a flame ionization detector (GC-FID) was used as a reference analytical technique, which enabled to obtain reliable quantitative determinations of toluene concentration in the samples. A commercially available absorption liquid dedicated to non-polar compounds was used as an absorbent. The process was carried out in two identical systems: in first, pure toluene was absorbed and in the second, toluene vapor contaminated with acetone. This approach allowed verifying the selectivity of the prepared MLR calibration model for process control in the case of the presence of more or less expected pollutants in the treated gas. The results obtained with the gas sensor array were related to the reference technique and they confirm the usefulness and advisability of using these devices to monitor the absorption processes as a cheaper and more time-efficient alternative to chromatographic methods. The root mean square error (RMSE) in absorptivity determination between the results received with the analytical and sensor techniques was 0.019 and 0.041 when treating pure toluene vapors and its vapors with acetone, respectively. Compared to instrumental techniques, sensor matrices are technologically less complex, useful for laboratory purposes, as well as showing application potential for field studies. However, it is necessary to develop more sensitive and selective chemical gas sensor arrays and better master advanced data processing and identification techniques.

8

A Review on Feasible and Reliable Underwater Wireless Optical Communication System for achieving High Data Rate and Longer Transmission Distance

Joseph Lenin, Anandan Sangeetha

International Journal of Electronics and Telecommunications

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2022

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Vol. 68. No. 4

815--823

EN

Underwater Wireless Optical Communication (UWOC) offers significant research prospective with major challenges in the design and implementation. UWOC is capable of providing high rate of data transmission across large distances. This paper attempts to focus on the intricacies of practical implementations and open research issues of UWOC systems. Critical advances and progresses made in the field, modelling techniques and link design challenges are summarised. The purpose of this review is to give suggestions towards feasible and reliable UWOC design with improved performance. Finally the major points are summarized so that it will assist the future research in UWOC.

9

Water absorption behavior and its effect on Charpy impact test of jute yarn reinforced polyester composites

Djeghader Djamel, Redjel Bachir

Composites Theory and Practice

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2022

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R. 22, nr 2

65--71

EN

Plates of bidirectional jute/polyester composite material were manufactured by the contact molding method. These plates were cut to form notched test pieces 80x15x4 mm and immersed in water (1, 10, 30, 90, 180 and 270 days) in order to study the impact behavior of this material. The studied composite exhibited a water saturation limit after an immersion period of approximately 30 days, with Fickian diffusion of water within the material. Williams’ method based on linear elastic fracture mechanics was used to calculate impact toughness GIC, which is due to the intrinsic characteristics of the material.

10

Shrinkage and Absorption of Sand Concrete Containing Marble Waste Powder

Djebien Rachid, Abbas Yassine, Bouabaz Amel, Ziada Yasser Nacereddine

Civil and Environmental Engineering Reports

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2022

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Vol. 32, no. 1

240--254

EN

In the context of growing scarcity of natural resources, the high demand of aggregates and the difficulties to open new quarries, several studies were carried out to study the possibility of reuse of waste and industrial by-products to replace traditional materials which would run out, replace materials when transport distances increase to reduce construction costs and protect the environment. This experimental study aims to investigate the effect of marble waste used as powder on the shrinkage and absorption of sand concrete in order to reuse it in the production of sand concrete. To achieve this goal, several sand concrete mixtures containing different substitutions rates of marble powder (4, 8 and 12%), and different Water / Cement ratio (0.71, 0.74, 0.77) were produced. Then, the evolution of the shrinkage and absorption values of sand concrete mixtures was studied. The obtained results showed that marble waste powder plays a positive role in reducing of shrinkage and absorption values of sand concrete and lead to the production of eco-friendly sand concrete.

11

Electromagnetic wave absorption performance of UHPC incorporated with carbon black and carbon fiber

Xu Shenchun, Yang Yekai, Wu Chengqing, Liu Kai

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 2

art. no. e71, 1--17

EN

This study focuses on the electromagnetic wave absorption performance (EWAP) of ultra-high-performance concrete (UHPC) incorporated with carbon black (CB) and carbon fiber (CF) in 2-18 GHz frequency range (required for the radar wave absorbing materials). The reflectivity of the traditional UHPC was investigated and compared to the cement-based composites reported in the literatures, so as to illustrate the advantages of novel UHPCs with respect to EWAP. Afterwards, the effect of CB and CF on the compressive strength, complex permittivity and reflectivity of the novel UHPCs was investigated. The microstructure of the novel UHPCs was also explored via scanning electron microscopy to illustrate the mechanism of performance enhancement on incorporating CB and CF. The results indicated that EWAP of the traditional UHPC was similar or inferior (at specific frequencies) to the literature reported cement-based composites. However, EWAP of the novel UHPCs was significantly improved after reinforcing with CB or CF. A positive effect of CB and CF was also observed on the compressive strength of the developed UHPCs. This study provides avenues for the use of UHPCs in protecting structures for absorbing the electromagnetic waves and safeguarding these structures against extreme loads, including blast and penetration.

12

Badania separacji CO2 i N2 na membranach SILM na podłożu ceramicznym AL2O3

Rotkegel Adam, Ziobrowski Zenon

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2021

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nr 25

45--56

PL

W pracy przedstawiono wyniki badań separacji ditlenku węgla i azotu na ceramicznych membranach impregnowanych cieczami jonowymi [Emim][Ac] (octan 1-etylo-3-metyloimidazolowy) oraz [Emim][BF4] (4-fluoroboran 1-etylo-3-metyloimidazolowy). Badania przeprowadzono dla membrany ceramicznej firmy Inopor w temperaturach 20-60°C dla ciśnień 1-7 bar. Ciecz jonową nanoszono metodą pokrywania. Stwierdzono, że otrzymane membrany SILMs charakteryzują się niewielkimi strumieniami masowymi oraz dużymi wartościami selektywności.

EN

The experimental results of carbon dioxide and nitrogen separation on ceramic membranes impregnated with ionic liquids [Emim][Ac] (1-ethyl-3-methylimidazolium acetate) and [Emim][BF4] ((1-ethyl-3methylimidazolium tetra fluoroborate) are presented. Ceramic membranes made by Inopor were investigated in 20-60°C and in the pressure range 1-7 bar. The ionic liquid was introduced into ceramic support by coating method. It was found, that prepared SILMs are characterized by small mass fluxes and high selectivities.

13

Optical investigation of bovine grey and white matters in visible and near-infrared ranges

Shahin Ali, Bachir Wesam, El-Daher Moustafa Sayem

Polish Journal of Medical Physics and Engineering

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2021

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Vol. 27, Iss. 1

99--107

EN

Introduction: Due to enormous interests for laser in medicine and biology, optical properties characterization of different tissue have be affecting in development processes. In addition, the optical properties of biological tissues could be influenced by storage methods. Thus, optical properties of bovine white and grey tissues preserved by formalin have been characterized over a wide wavelength spectrum varied between 440 nm and 1000 nm. Materials and Methods: To that end, a single integrating sphere system was assembled for spectroscopic characterization and an inverse adding-doubling algorithm was used to retrieve optical coefficients, i.e. reduced scattering and absorption coefficients. Results: White matter has shown a strong scattering property in comparison to grey matter. On the other hand, the grey matter has absorbed light extensively. In comparison, the reduced scattering profile for both tissue types turned out to be consistent with prior works that characterized optical coefficients in vivo. On the contrary, absorption coefficient behavior has a different feature. Conclusion: Formalin could change the tissue's optical properties because of the alteration of tissue's structure and components. The absence of hemoglobin that seeps out due to the use of a formalin could reduce the absorption coefficient over the visible range. Both the water replacement by formalin could reduce the refractive index of a stored tissue and the absence of hemoglobin that scatters light over the presented wavelength range should diminish the reduced scattering coefficients over that wavelength range.

14

Performance evaluation of non-water absorption coefficient partitioning algorithms in optically complex coastal waters of Kochi and Goa, India

Kolluru Srinivas, Gedam Shirishkumar S., Inamdar Arun B.

Oceanologia

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2021

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No. 63 (4)

420--437

EN

Absorption coefficient partitioning algorithms (APAs) were developed to partition the total absorption coefficient (a(λ)) or total non-water absorption coefficient (anw(λ)) into the absorption subcomponents, i.e., absorption due to phytoplankton aph(λ), colored dissolved organic matter (CDOM) aƍ(λ) and non-algal particulate matter ad(λ), λ is the wavelength. Absorption coefficients of CDOM and non-algal particulate matter are generally combined due to a similarity in exhibited spectral shape and represented as colored detrital matter (CDM) absorption coefficient, adƍ(λ). This study focuses on the applicability of five APAs Schofield's, Lin's, Zhang's, Stacked Constraints Model (SCM) and Generalized Stacked Constraints Model (GSCM), in deriving the absorption subcomponents from anw(λ) in optically complex coastal waters of Kochi and Goa, India. The average spectral Mean Absolute Percentage Errors (MAPE) obtained for all models in the retrieval of aph(λ), ad(λ), aƍ(λ) and adƍ(λ) lie in the ranges of 26-44%, 37-45%, 34-65% and 42-56%. Slopes of adƍ(λ), aƍ(λ) and ad(λ) as indicated by Sdƍ, Sƍ and Sd are derivable from GSCM, Schofield and Lin's models only. GSCM model exhibited good retrieval capability of Sd with MAPE values of 22% and a correlation coefficient of 0.74. In retrieval of Sƍ parameter, none of the models demonstrated satisfactory performance. Overall, the GSCM and Schofield's models demonstrated good performance in the retrieval of absorption subcomponents, aph(λ), adƍ(λ), ad(λ) and Sd. Effect of applying baseline correction to ad(λ) on model performance is studied. Tuning with in situ data can further improve the absorption subcomponent and slope parameter retrieval capability of the models.

15

Purification of Synthetic Gas from Fine Coal Waste Gasification as a Clean Fuel

Faizal Muhammad, Said Muhammad, Nurisman Enggal, Aprianti Nabila

Journal of Ecological Engineering

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2021

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Vol. 22, nr 5

114--120

EN

The presence of CO2 in the syngas is attracting more attention in terms of reducing the greenhouse gas emissions in its utilisation. The aim of this study was to purify syngas from the CO2 content of fine coal gasification. Fine coal is gasified with and without absorption using CaO, which is hydrated to Ca(OH) 2 in the modified updraft gasifier at 450–700 °C. Apart from investigating the CO2 absorption process, the gasification process also evaluates the influence of temperature in terms of its synergy with Ca(OH) 2. The best conditions for the gasification process are achieved at 700 °C. The content of CO2 was proven to be well absorbed, which is characterised by a decrease in the CO2 content and an increase in H2 in syngas. After the absorption process, the H2 content obtained increased from 42.6 mole% to 48.8 mole% of H2 at 700°C. The H2 ratio also increased after absorption to 2.57 from the previous value of 2.23. The highest absorption efficiency of CO2 by Ca(OH) 2 occurred at 700°C at 50.63%. With an increase in temperature in the gasification process with absorption, the CO2 content decreased dramatically from 16.9 mole% to 3.9%. Ca(OH) 2 has good absorption power at CO2 at high temperatures.

16

Comparative Analysis of Three Different Negative Emission Technologies: BECCS, Absorption and Adsorption of Atmospheric CO2

Talei Saeed, Soleimani Zahra

Civil and Environmental Engineering Reports

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2021

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Vol. 31, no. 3

99--117

EN

Negative Emission Technologies (NETs) are generally considered as vital methods for achieving climate goals. To limit the rise in the global average temperature below 2°C, a large number of countries that participated in the Paris agreement was virtually unanimous about the effective collaboration among members for the reduction of CO2 emissions throughout this century. NETs on the ground that can remove carbon dioxide from the atmosphere, provide an active option to achieve this goal. In this contribution, we compare limiting factors, cost, and capacity of three different NETs, including bioenergy with carbon capture and storage (BECCS), absorption and adsorption. Although there are several advantages for capturing CO2, still some constraints regarding the high operational cost of NETs and industrial condition of these technologies as a method of climate change mitigation is not clear. Thereby no single process can be considered as a comprehensive solution. Indeed, any developed technologies, in turn, have a contribution to the reduction of CO2 concentration. Extensive research needs to be done to assess and decrease NETs costs and limitations.

17

Acoustic Panels Inspired by Nature

Borkowski Bartłomiej, Suder-Dębska Katarzyna, Wiciak Jerzy, Szlachta Anna Maria

Archives of Acoustics

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2021

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Vol. 46, No. 1

135--146

EN

The article presents the approach to the design process of acoustic panels based on the scientific research. This approach is based on combining the technical and the design competences to develop the innovative product value for the concept of acoustic panels. The article presents the concepts of two new acoustic panels – an absorbing and scattering panel and a panel reflecting sound waves. The first part of the article presents the starting point for the presented project – the acoustic research and the inspiration for both types of presented solutions. Next, the materials possible to use were discussed, which could reproduce the natural acoustic properties of the lava and glacier caves. The next part presents consecutive stages of the product development in a modern form, ensuring the expected acoustic properties. The last part of the article presents a fully functional solution and proposes further research and development directions.

18

Badania efektywności rozdziału CO2/N2 na membranach silm o podłożu ceramicznym

Rotkegel Adam, Ziobrowski Zenon

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2020

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nr 24

65--81

PL

W pracy przedstawiono wyniki badań separacji ditlenku węgla i azotu na ceramicznych membranach impregnowanych cieczami jonowymi [Emim][Ac] ] (octan 1-etylo-3-metyloimidazolowy) oraz Emim][Tf2N] (1-etylo-3-metylolimidazolowy bis[tri(fluorometano)sulfonylo)]imidek). Badania przeprowadzono dla membrany ceramicznej firmy Inopor w temperaturach 20-60°C dla ciśnień 1-7 bar. Ciecz jonową nanoszono metodą pokrywania oraz zanurzania. Stwierdzono, że otrzymane membrany SILMs charakteryzują się niewielkimi strumieniami masowymi oraz dużymi wartościami selektywności.

EN

The experimental results of carbon dioxide and nitrogen separation on ceramic membranes impregnated with ionic liquids [Emim][Ac] (1-ethyl-3-methylimidazolium acetate) and Emim][Tf2N] (1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide) are presented. Ceramic membranes made by Inopor were investigated in 20-60°C and in the pressure range 1-7 bar. The ionic liquid was introduced into ceramic support by coating and soaking. It was found, that prepared SILMs are characterized by small mass fluxes and high selectivities.

19

Surface desalinated layer distribution in the Kara Sea determined by shipboard and satellite data

Glukhovets Dmitry I., Goldin Yury A.

Oceanologia

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2020

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No. 62 (3)

364--373

EN

This study reports the propagation dynamics of the Kara Sea surface desalinated layer (SDL) during the summer and autumn seasons. We analysed shipboard measurements data collected in 2013-2018 and MODIS ocean colour data that correlated with the shipboard ones. We formulated a comparatively strict criterion to determine the SDL border based on satellite data. For that, we analyzed the shipboard flow-through measuring system data obtained while crossing the surface desalinated layer border. Further, we used a regional algorithm to process the satellite data and estimate the coloured dissolved organic matter absorption coefficient for the Kara Sea. The results demonstrate a significant effect of the wind regime on the interseasonal and interannual variability of the transformation of the SDL boundaries. The positions of the surface desalinated layer boundaries at different times during 2013-2018 are given. The obtained results are important for calculating the heat balance and analyzing the Kara Sea bio-productivity.

20

The vibration energy absorption of tractor operator exposed to vertical whole-body vibration under work of the aggregate tractor-round baler

Kromulski Jacek, Szczepaniak Jan, Gajek Dariusz, Mac Jarosław, Wojciechowski Jacek, Zawada Michał

Journal of Research and Applications in Agricultural Engineering

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2020

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Vol. 65, nr 1

14--20

EN

Humans are most sensitive to whole body vibration (WBV) within the frequency range of 1 to 20 Hz. Whole-body vibration can cause fatigue, stomach problems, headache. After daily exposure over a number of years, whole-body vibration can affect the entire body and result in a number of health disorders. Workers driving tractors or other vehicles are especially at risk of being exposed to WBV. On the basis of the guidance provided in ISO 2631-1 to relate vibration exposure with the risks of health effects are established based on absorbed power. The 4-DOF dynamic model developed by Wan and Schimmels is recommended for the study of biodynamic responses of seated human subjects under vertical whole body vibration. This model of the human body is used to estimate the absorbed power distributed in head, upper torso, lower torso and thighs. The vibration energy (power) absorption of seated human that is exposed to vertical whole-body vibration are investigated under work of the aggregate tractor-round baler.

PL

Ludzie są najbardziej wrażliwi na drgania o działaniu ogólnym w zakresie częstotliwości od 1 do 20 Hz. Drgania o działaniu ogólnym mogą powodować zmęczenie, problemy żołądkowe, ból głowy. Po codziennej, wieloletniej, ekspozycji na drgania o oddziaływaniu ogólnym może zostać powstać szereg zaburzeń zdrowotnych. Pracownicy prowadzący ciągniki lub inne pojazdy są szczególnie narażeni na kontakt z drganiami o oddziaływaniu ogólnym. Na podstawie wytycznych zawartych w normie ISO 2631-1 istnieje powiązanie narażenia na wibracje z ryzykiem skutków zdrowotnych na podstawie pochłoniętej mocy drgań. Model biodynamiczny o czterech stopniach swobody 4-DOF opracowany przez Wana i Schimmelsa jest zalecany do badania reakcji siedzącego kierowcy na pionowe drgania o oddziaływaniu ogólnym. Model ten pozwala wyznaczyć pochłoniętą moc drgań w poszczególnych elementach ciała człowieka: głowa, górną część tułowia, dolną część tułowia oraz uda. Model ten zastosowano do badania absorpcji mocy drgań przez operatora agregatu ciągnik-prasa zwijająca