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1

Effect of Methyl Silicone Oil to Moisture Resistance of Sodium Silicate Sands by Microwave Hardening

Wang Huafang, Gao Xiang, Yang Lei, He Wei, Lu Jijun

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

43--47

EN

The sodium silicate sands hardened by microwave have the advantages of high strength, fast hardening speed and low residual strength with the lower addition of sodium silicate. However, the sodium ion in the sands will absorb moisture from the atmosphere, which would lead to lower storing strength, so the protection of a bonding bridge of sodium silicate between the sands is crucial. Methyl silicone oil is a cheap hydrophobic industrial raw material. The influence of the addition amount of methyl silicone oil modifier on compressive strength and moisture absorption of sodium silicate sands was studied in this work. The microscopic analysis of modified before and after sodium silicate sands has been carried on employing scanning electron microscopy(SEM) and energy spectrum analysis(EDS). The results showed that the strength of modified sodium silicate sands was significantly higher than that of unmodified sodium silicate sands, and the best addition of methyl silicone oil in the quantity of sodium silicate was 15%. It was also found that the bonding bridge of modified sodium silicate sands was the density and the adhesive film was smooth, and the methyl silicone oil was completely covered on the surface of the sodium silicate bonding bridge to protect it.

2

Microstructure silica leached by NaOH from semi-burned rice husk ash for moisture adsorbent

A’yuni D.Q., Subagio A., Hadiyanto H., Kumoro A.C., Djaeni M.

Archives of Materials Science and Engineering

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2021

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Vol. 108, nr 1

5--15

EN

Purpose: This work aims to study the water vapor adsorption property of fine silica particles from semi-burned rice husk ash. The semi-burned rice husk ash is selected as the raw material since it contains high silica and is easily found as a by-product of pottery furnace combustion. Design/methodology/approach: The silica adsorbent from semi-burned rice husk ash was prepared through a sol-gel method using various NaOH concentrations. In doing so, the different pH precipitation was also observed. Here, the fine silica powder was obtained by pulverizing dry sol-gel. The product characterizations were conducted based on water adsorption capacity at different air relative humidity. Findings: The results show no significant effects of different treatments in the extraction and gelation process. The fine silica particles exhibit large porous surfaces with agglomerated nano-sized particles that formed pores. This porous structure is related to the distributions of pore size of each sample, which mostly obey the mesoporous characteristics. From sorption isotherm, weak adsorbent-adsorbate bonding was observed and demonstrated multilayer adsorption of mesoporous materials. Research limitations/implications: The study of water adsorption was carried out at room temperature, which can change at any time, even though has no significant effect on the humidity. However, it is needed to study the adsorption in an incubated area to receive a constant temperature. Practical implications: The products namely silica prepared from semi-burned rice husk ash show a high moisture uptake, especially at a high relative humidity region. This property can be comparable with the other silica preparation methods. So, this product can be a highly potential adsorbent for air or gas dehumidification systems. Originality/value: The silica-based semi-burned rice husk ash as a water adsorbent is more sustainable than commercial silica. This is a positive contribution to find a potentially develop water vapor adsorbent with good adsorption capacity. Besides, the synthesis process is a simple and low-cost process.

3

Nonlocal zigzag analytical solution for Laplacian hygrothermal stress analysis of annular sandwich macro/nanoplates with poor adhesions and 2D-FGM porous cores

Alipour M. M., Shariyat M.

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 4

1211--1234

EN

A zigzag nonlocal model is presented for annular/circular sandwich macro- and nanoplates with bidimensional graded porous cores and weak interfacial adhesions. This is the first time that a stress analysis is performed in the framework of Eringen's nonlocality concept. In this regard, after determination of the displacements by utilizing a power series solution, the governing Laplacian equations of the stress components in terms of the displacement components are solved in a post-processing stage, using a power series solution in terms of stress parameters. Effects of the thermal stresses and material degradation and deterio-ration due to the temperature rise and moisture absorption are also taken into account. To guarantee continuity of the transverse shear and normal stresses, the bonding layers are modeled by spring elements. To present a general model, it is assumed that the core porosity changes in both radial and transverse directions. It is the first time that the effects of the porosity are investigated on transverse distributions of the displacement and stress com-ponents. The results have captured the significant effects of the nonlocality, moisture absorption, and bond strength on the stress and lateral deflection results, and especially, the abrupt changes in the in-plane displacement and stress components at the interfaces.

4

Wpływ surfaktantów na pochłanianie i oddawanie wody przez nawóz ZnIDHA

Januszkiewicz K., Mrozek-Niećko A., Różański J.

Inżynieria i Aparatura Chemiczna

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2018

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Nr 2

29--30

PL

Przedstawiono wpływ trzech surfaktantów: poliglukozydu, oksyetylatu alkoholu tłuszczowego i trisiloksanu na szybkość pochłaniania i oddawania wilgoci przez stały nawóz ZnIDHA (chelat cynku i soli sodowej kwasu D,L-asparaginowego). Z przeprowadzonych badań wynika, że trisilokasan oraz oksyetylat alkoholu tłuszczowego wydłużają o kilka godzin czas, w którym nawóz w wilgotnym powietrzu będzie występował w formie stałej. Żaden z użytych surfaktantów nie powodował wydłużenia czasu utrzymywania się wody w nawozie.

EN

The paper presents an influence of three surfactants: polyglucoside, fatty alcohol ethoxylate and trisiloxane on the rate of absorption and moisture removal by ZnIDHA fertilizer (D, L-Aspartic acid, N-(1,2 dicarboxyethyl) disodium salt of Zn). The studies showed that trisiloxane and fatty alcohol ethoxylate extended for a few hours the time in which fertilizer in moist air is present in a solid form. None of surfactants used increased the time of water holding in fertilizer.

5

Procesy pochłaniania wilgoci z otoczenia i wysychania na przykładzie wierzchnich warstw form odlewniczych

Kaźnica N., Zych J.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 4 spec.

63--66

PL

W pracy przedstawiono wyniki badania procesów: pochłaniania wilgoci z otoczenia oraz wysychania wierzchnich warstw form piaskowych. Badania obejmowały trzy rodzaje mas formierskich – jedną ze spoiwem nieorganicznym (uwodniony krzemian sodu) i dwie ze spoiwami organicznymi (żywica furfurylowa oraz żywica alkidowa). Badania sorpcji prowadzono na prototypowym stanowisku badawczym pozwalającym na utrzymanie stałej, wysokiej temperatury otoczenia (28–33 °C) oraz wilgotności względnej powietrza powyżej 95%. Badania desorpcji prowadzono na analogicznym stanowisku badawczym zapewniającym odpowiednio niższe wartości wilgotności względnej powietrza oraz temperatury. W obu przypadkach wykorzystano metodę grawimetryczną. Na podstawie analizy otrzymanych wyników wykazano, że wierzchnie warstwy form odlewniczych pochłaniają wilgoć z otoczenia z różną intensywnością, uzależnioną między innymi od ich składu. Jednocześnie, wszystkie zawilgocone badane masy poddane procesowi wysychania oddawały wilgoć do otoczenia. Krzywe sorpcji i desorpcji nie pokrywają się. W przypadku desorpcji zawartość końcowa wilgoci w wierzchnich warstwach form odlewniczych jest większa dla wszystkich badanych mas, niezależnie od rodzaju masy formierskiej.

EN

The results of investigations of the sorption and desorption process of surface layers of sand moulds are presented in the paper. Investigations comprised three kinds of moulding sands with one inorganic binder (hydrated sodium silicate) and two organic binders: (furfuryl resin and alkyd resin). Tests of sorption process were performed on the prototype research stand allowing to maintain a constant, high temperature of surroundings (28–33 °C) and the relative air humidity above 95%. Tests of desorption process were performed on the analogical research stand ensuring lower value of temperature and the air humidity. The gravimetric method was applied in both measurements. On the bases of achieved results it was shown that surface layers of sand moulds absorb water vapour from surroundings with various intensity which is determined of the chemical composition. Simultaneously, all of the moistened moulding sands which were subjected to the drying process were given moisture to the surroundings back. Sorption and desorption processes curves do not coincide. In case of desorption process the moisture content in the surface layers of all the tested moulding sands is higher irrespective of the kind of moulding sand.

6

Water-Soluble Alginate Fibres for Medical Applications

Mikołajczyk T.

Fibres & Textiles in Eastern Europe

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2001

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Vol. 9, no. 3 (34)

20--23

EN

The paper concerns the development of conditions for the manufacture of water-soluble sodium alginate fibres with very good moisture absorption properties and a high capability to imbibe water from a wet substrate. Their tenacity at a level of 12 N/tex makes it possible to process them into medical dressing materials. Antibacterial properties of these fibres can be obtained by adding an antibiotic into the fibre-spinning solution during the technological process.

PL

Opracowano warunki wytwarzania rozpuszczalnych w wodzie włókien z alginianu sodowego o bardzo dobrych właściwościach sorpcyjnych i wysokiej zdolności do pochłaniania wody z wilgotnego podłoża. Wytrzymałość właściwa na poziomie 12 cN/tex umożliwia ich przerób włókienniczy na środki opatrunkowe. Wprowadzenie antybiotyku do roztworu przędzalniczego nadaje włóknom właściwości antybakteryjne.

7

Effect of the Porous Structure of Gelatine-Polyacrylonitrile Graft Copolymer Fibres on their Absorption and Strength Properties

Mikołajczyk T., Czapnik A.

Fibres & Textiles in Eastern Europe

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2001

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Vol. 9, no. 1 (32)

36--39

EN

The effect of porous structure of gelatine-polyacrylonitrile graft copolymer fibres on their moisture absorption and mechanical properties has been analysed. It has been found that it is possible to obtain fibres alternatively with either better absorption properties or higher strength properties depending on the character of the fibre porous structure formed. Fibres with lower tenacity can be used in blends with other synthetic fibres.

PL

Przeprowadzono analizę porównawczą wpływu struktury porowatej na właściwości sorpcyjne i wytrzymałościowe włókien z kopolimeru szczepionego żelatyna-poliakrylonitryl. Stwierdzono, iż charakter wytwarzanej w optymalnych warunkach formowania struktury porowatej włókien limituje możliwość uzyskiwania jednocześnie dobrych właściwości wytrzymałościowych, z zachowaniem wysokich właściwości sorpcyjnych.

8

Structure and properties of gelatine-polyacrylonitrile-grafted copolymer fibres

Mikołajczyk T., Czapnik A.

Zeszyty Naukowe. Włókiennictwo / Politechnika Łódzka

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2000

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z. 58

269-276

EN

Chemical modification of gelatine recovered from chrome tanned leathers by grafting acrylonitrile makes it possible to prepare fibres from a new material constituting gelatine-polyacrylonitrile grafted copolymer. Such fibres should be characterised by irnproved moisture absorption characteristics and susceptibiIity to biodegradation. Trials of fibre spinning from such a copolymer are described in paper.