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Number of results: 36
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Abstract

This paper discussed the effect of the addition of silica fume (2 wt.% and 4 wt.%) and alumina (2 wt.% and 4 wt.%) on the properties of fly ash geopolymer concrete. The fly ash geopolymer concrete achieved the highest 28-day compressive strength with 2 wt.% of silica fume (39 MPa) and 4 wt.% of alumina (41 MPa). The addition of 2 wt.% of silica fume increased the compressive strength by 105% with respect to the reference geopolymer (without additive). On the other hand, the compressive strength surged by 115% with 4 wt.% of alumina compared to the reference geopolymer. The addition of additives improved the compactness of the geopolymer matrix according to the morphology analysis.
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Authors and Affiliations

Fong Sue Min
1
Heah Cheng Yong
1 2
ORCID: ORCID
Liew Yun Ming
1 3
ORCID: ORCID
Mohd Mustafa Al Bakri Abdullah
1 3
ORCID: ORCID
Hasniyati Md Razi
4
Foo Wah Low
5
Ng Hui-Teng
1 2
Ng Yong-Sing
1 2

  1. Centre of Excellence Geopolymer and Green Technology (CEGeoGTech), Universiti Malaysia Perlis (UniMAP), 01000 Perlis, Malaysia
  2. Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02600 Perlis, Malaysia
  3. Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 01000 Perlis, Malaysia
  4. Reactor Technology Center, Technical Support Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Malaysia
  5. Department of Electrical & Electronic Engineering, Lee Kong Chian Faculty of Engineering & Science, Universiti Tunku Abdul Rahman, Bandar Sungai Long, 43000 Kajang, Malaysia
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Abstract

The goal of this article is to application of non-silica sands based on alumininosilicates as an alternative of traditionally used chromite sand for alloyed steel and iron castings. Basic parameters as bulk density, pH value of water suspension, refractoriness, grain shape of the testing sands were evaluated. Also mechanical properties of furan no-bake moulding mixtures with testing sand were determined. Finally, the influence of non-silica sand on casting quality was evaluated via semi-scale under normal casting production for sand characterization Optimization of production process and production costs were described.

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Authors and Affiliations

J. Beňo
M. Poręba
ORCID: ORCID
T. Bajer
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Abstract

The granary weevil, Sitophilus granarius (L.), is one of the most important internal feeders of stored grain. Nanotechnology has become one of the most promising new approaches for pest control in recent years. In our screening program, laboratory trials were conducted to determine the effectiveness of silica nanoparticles (SNPs) and zinc nanoparticles (ZNPs) against the larval stage and adults of S. granarius on stored wheat. Nanoparticles of silica and zinc were synthesized through a solvothermal method. They were then used to prepare insecticidal solutions of different concentrations and tested on S. granarius. Silica nanoparticles (SNPs) were found to be highly effective against S. granarius causing 100% mortality after 2 weeks. ZNPs were moderately effective against this pest.

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Authors and Affiliations

Mohammad Rouhani
Mohammad Amin Samih
Mehdi Zarabi
Khalil Beiki
Mohammad Gorji
Mohammad Reza Aminizadeh
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Abstract

Describes how to obtain a soluble sodium silicate with a density of 1.40 g/cm3, 1.45 g/cm3, 1.50 g/cm3, and silica module M = 2.1 obtained from the silica- sodium glass with module M = 3.3 and M = 2.1. Residual (final) strength of molding samples made with these binders, were determined at temperatures corresponding to the characteristic temperatures of phase and temperature transitions of silica gel. Indicated the type of soluble sodium silicate capable of obtain the smallest value of the final strength of molding sand in the specified range of temperatures.

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Authors and Affiliations

A. Baliński
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Abstract

Substituting of ethyl silicate with ecologic sols of colloidal silica in the investment casting technology, resulting from the increased demands concerning environmental protection, caused the prolongation of production cycle for precision castings produced in multi-layer thin-walled ceramic shell moulds. Modification of Sizol 030 binder with benzoyl peroxide, proposed in the paper, was aimed at restriction of time needed for realization of a single layer of the shell mould, and by the same, of such a mould as a whole. Examination of kinetics of the drying process were held for the layers made of prepared moulding material and the influence of binder modification on the mould curing time was determined.
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Authors and Affiliations

M. Nadolski
Z. Konopka
M. Łągiewka
A. Zyska
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Abstract

Alkali-aggregate reactivity (AAR) is one of the major causes of damage in concrete. Potential susceptibility of aggregates to this reaction can be determined using several methods. This study compares gravel alkali reactivity results obtained from different tests conducted on coarse aggregates with complex petrography. The potential for the reactivity in the aggregates was revealed in the chemical test using treatment with sodium hydroxide. Optical microscopy, scanning electron microscopy and X-ray diffraction were used to identify the reactive constituents. The expansion measured in the mortar bars test confirmed that the aggregate was potentially capable of alkali silica reactivity with consequent deleterious effect on concrete.

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Authors and Affiliations

Z. Owsiak
P. Czapik
J. Zapała-Sławeta
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Abstract

This study describes the creation of a low-cost silica material using a silicate extract as a precursor. This precursor is made from inexpensive palm frond waste ash through a simple calcination process at 500°C and a green extraction with water. Nitrogen adsorption-desorption, FTIR analyses, and transmission electron microscopy were used to characterize the samples. The surface area of the obtained mesoporous silica ash material was 282 m2/g1, and the pore size was 5.7 nm. For the adsorption of copper ions, an excellent adsorbent was obtained. The maximum copper ion adsorption capacity of this inexpensive silica ash-based adsorbent for removing heavy metal ions Cu(II) from aqueous solutions was 20 mg/g, and the effect of pH, temperature, and time on its adsorption capacity were also investigated. In addition, the adsorption isotherms were fi tted using Langmuir and Freundlich models, and the adsorption kinetics were evaluated using pseudo-fi rst-order and pseudo-secondorder models. The results demonstrated that the synthesized adsorbent could effectively remove heavy metal ions from aqueous solutions at pH levels ranging from 2 to 5. The adsorption isotherms followed the Langmuir model, and the kinetic data fi t the pseudo-second-order mode well. The thermodynamic results Negative values of G° indicate that the adsorption process was spontaneous, and negative values of entropy S° indicate that the state of the adsorbate at the solid/solution interface became less random during the adsorption process. According to the findings, prepared silica from palm waste ash has a high potential for removing heavy contaminating metal ions Cu (II) from aqueous solutions as a low-cost alternative to commercial adsorbents.
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Authors and Affiliations

Fatima A. Al-Qadri
1
Alsaiari Raiedhah
1

  1. Department of Chemistry, College of Science and Art in Sharurah, Najran University,Kingdome of Saudi Arabia
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Abstract

Optical waveguides (WGs) are widely used as interconnects in integrated optical circuits both for telecommunication and sensing applications. There are different kind of optical WG designs that offers different guiding parameters, opening a vast number of possibilities. A silica-titania (SiO2:TiO2) rib WG is discussed and examined by a numerical analysis in this article with a great emphasis on the analysis of bending losses and optimization. A modal analysis for different basic parameters of the WG is presented with a detailed wavelength-based modal analysis. Various potential fabrication methods are discussed, however, a sol-gel method and dip-coating deposition technique are proposed for the low-cost development of such WGs. Moreover, an approach towards minimizing the bending losses by adding an upper cladding layer on the rib WG is presented and described.
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Authors and Affiliations

Muhammad Shahbaz
1
ORCID: ORCID
Łukasz Kozlowski
1
Muhammad A. Butt
1
ORCID: ORCID
Ryszard Piramidowicz
1
ORCID: ORCID

  1. Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, Koszykowa 75, 00-662 Warszawa, Poland
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Abstract

We have numerically studied different designs of technologically feasible microstructured fibers with a germanium-doped core in order to obtain normal dispersion reaching possibly far in the mid infrared. Hexagonal, Kagome and the combination of both geometries were numerically examined with respect to different constructional parameters like pitch distance, filling factor of air holes, number of layers surrounding the core, and level of germanium doping in the core. Our analysis showed that the broadest range of normal dispersion reaching 2.81 μm, while keeping an effective mode area smaller than 30 μm2, was achieved for a hexagonal lattice and a 40 mol% GeO2 doped core. The proposed fibers designs can be used in generation of a normal dispersion supercontinuum reaching the mid-IR region.

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Authors and Affiliations

J. Biedrzycki
K. Tarnowski
W. Urbańczyk
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Abstract

Dissolution of Si in Al-5 mass%Mg alloy melt by the reduction of SiO2 and its effect on microstructure formation of the alloy after solidification were investigated. Al-5 mass%Mg alloy without silica powder had approximately 0.05 mass%Si as an impurity. No significant difference in Si content was observed after the reaction with silica for 10 min, while the Si content increased up to about 0.12 mass% after 30 min. From the microstructure analysis and calculation of Scheil-Gulliver cooling, it was considered that as-cast microstructures of Al-5 mass%Mg-1 mass% SiO2 alloys had the distribution of eutectic phase particles, which are comprised of β-Al3Mg2 and Mg2Si phases. Based on the phase diagrams, only limited amount of Mg can be selectively removed by silica depending on the ratio of Si and Mg. Addition of silica of more than approximately 1.5 mass% in Al-5 mass%Mg alloy led to the formation of spinel and removal of both Mg and Al from the melt.
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Bibliography

[1] J.R. Davis, ASM International, Aluminum and Aluminum Alloys, Materials Park 1993.
[2] T. Hashiguchi, H. Sueyosh, Mater. Trans. 51, 838 (2010).
[3] B.H. Kim, S.H. Ha, Y.O. Yoon, H.K. Lim, S.K. Kim, D.H. Kim, Mater. Lett. 228, 108 (2018).
[4] S.H. Ha, B.H. Kim, Y.O. Yoon, H.K. Lim, S.K. Kim, Sci. Adv. Mater. 10, 694 (2018).
[5] R. Muñoz-Arroyo, H.M. Hdz-García, J.C. Escobedo-Bocardo, E.E. Granda-Gutierrez, J.L. Acevedo-Dávila, J.A. Aguilar-Martínez, A. Garza-Gomez, Adv. Mater. Sci. Eng. 2014, 1 (2014).
[6] S.H. Ha, B.H. Kim, Y.O. Yoon, H.K. Lim, S.K. Kim, Sci. Adv. Mater. 10, 694 (2018).
[7] C.W. Bale, E. Bélisle, P. Chartrand, S.A. Decterov, G. Eriksson, A.E. Gheribi, K. Hack, I.H. Jung, Y.B. Kang, J. Melançon, A.D. Pelton, S. Petersen, C. Robelin, J. Sangster, P. Spencer, M.A. Van Ende, Calphad 54, 35 (2016).
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Authors and Affiliations

Sun-Ki Kim
1
ORCID: ORCID
Seong-Ho Ha
2
ORCID: ORCID
Bong-Hwan Kim
2
ORCID: ORCID
Young-Ok Yoon
2
ORCID: ORCID
Hyun-Kyu Lim
2
ORCID: ORCID
Shae K. Kim
2
ORCID: ORCID
Young-Jig Kim
1
ORCID: ORCID

  1. Sungkyunkwan University, School of Advanced Materials Science and Engineering, Suwon 16419, Republic of Korea
  2. Korea Institute of Industrial Technology (KITECH), Advanced Materials and Process R&D Department, Incheon 21999, Republic of Korea
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Abstract

The main problem in the cores production by cold-box method is the occurence of surface defects due to the tension generated by thermal expansion of the silica sand. One of the possibilities of eliminination is exchange of silica sand from another location. Another interesting factor is the type of used binder and its amount. However, even these measures donʹt guarantee sufficient quality. Foundries most often solve this problem by adding expensive additives to the core mixture. Foundries may have a dilemma in choosing the right additive. The aim of this paper was to investigate the effect of silica sand from two different locations, the effect of dosing the amount of binder and the addition of several types of commonly available additives on the quality of casting cavities. For this purpose, a total of 11 differently composed core sand mixtures were prepared, but only one of these mixtures was successful.
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Authors and Affiliations

P. Delimanová
1
ORCID: ORCID
I. Vasková
1
ORCID: ORCID
M. Bartošová
1
ORCID: ORCID
M. Hrubovčáková
1
ORCID: ORCID

  1. Technical University of Košice, Faculty of Materials, Metallurgy and Recycling, 9 Letná Str., 042 00 Košice, Slovakia
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Abstract

Foundry sand waste can be utilized for the preparation of concrete as a partial replacement of sand. The strength properties of M25 grade concrete are studied with different percentages of replacement of fine aggregates by foundry sand at 0%, 10%, 20%, 30%, 40%, and 50%. The optimum percentage of foundry sand replacement in the concrete corresponding to maximum strength will be identified. Keeping this optimum percentage of foundry sand replacement as a constant, a cement replacement study with mineral admixtures such as silica fume (5%, 7.5%, 10%) and fly ash (10%, 15%, 20%,) is carried out separately. The maximum increase in strength properties as compared to conventional concrete was achieved at 40% foundry sand replacement. Test results indicated that a 40% replacement of foundry sand with silica fume showed better performance than that of fly ash. The maximum increase in strengths was observed in a mix consisting of 40% foundry sand and 10% silica fume. SEM analysis of the concrete specimens also reveals that a mix with 40% foundry sand and 10% silica fume obtained the highest strength properties compared to all other mixes due to the creation of more C-H-S gel formations and fewer pores.

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Authors and Affiliations

K.V.S. Gopala Krishna Sastry
A. Ravitheja
T. Chandra Sekhara Reddy
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Abstract

The reaction of alkalis with aggregate containing reactive forms of silica (ASR) plays a significant role in shaping the durability of concrete, as the strongly hygroscopic reaction products generated lead to internal stress, causing its expansion and cracking. This study presents an extended analysis of corrosive processes occurring in mortars with reactive natural aggregate from Poland, using computed tomography and scanning microscopy methods. Numerous cracks in the grains and the surrounding cementitious matrix were observed, indicating a high degree of advancement of corrosive processes. Over time, the proportion of pores with reduced sphericity increased, indicating ongoing degradation of the mortars. The usefulness of computed tomography in studying the progress of ASR was demonstrated. Scanning microscopy confirmed that the cause of mortar degradation is the formed ASR gel with a typical composition, located within the volume of reactive grains, cracks propagating into the cementitious matrix, and accumulated in air voids.
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Authors and Affiliations

Justyna Zapała-Sławeta
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Abstract

Silica multichannel monoliths modified with zirconia, titania and alumina have been used as reactive cores of microreactors and studied in chemoselective reduction (MPV) of cyclohexanon/benzaldehyde with 2-butanol as a hydrogen donor. The attachment of metal oxides to the silica surface was confirmed by FT–IR spectroscopy, and dispersion of metal oxides was studied by UV–Vis spectroscopy. the catalytic activity of the lewis acid centres in both chemical processes decreased in the order zirconia > alumina > titania. This activity is in good agreement with dispersion and coordination of metal species. good stability of zirconia-grafted reactors was confirmed. high porosity of the monoliths and the presence of large meandering flow-through channels with a diameter of ca. 30 mm facilitate fluid transport and very effective mixing in the microreactors. The whole synthesis process is perfectly in line with trends of modern flow chemistry
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Authors and Affiliations

Katarzyna Maresz
Agnieszka Ciemięga
Julita Mrowiec-Białoń
Janusz M. Malinowski
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Abstract

The effects of silica additive (Poraver) on selected properties of BioCo3 binder in form of an aqueous poly(sodium acrylate) and dextrin (PAANa/D) binder were determined. Based on the results of the thermoanalytical studies (TG-DTG, FTIR, Py-GC/MS), it was found that the silica additive results in the increase of the thermostability of the BioCo3 binder and its contribution does not affect the increase in the level of emissions of organic destruction products. Compounds from group of aromatic hydrocarbons are only generated in the third set temperature range (420-838°C). The addition of silicate into the moulding sand with BioCo3 causes also the formation of a hydrogen bonds network with its share in the microwave radiation field and they are mainly responsible for maintaining the cross-linked structures in the mineral matrix system. As a consequence, the microwave curing process in the presence of Poraver leads to improved strength properties of the moulding sand (���� �� ). The addition of Poraver's silica to moulding sand did not alter the permeability of the moulding sand samples, and consequently reduced their friability. Microstructure investigations (SEM) of microwave-cured samples have confirmed that heterogeneous sand grains are bonded to one another through a binder film (bridges).

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Authors and Affiliations

S. Cukrowicz
S. Żymankowska-Kumon
B. Grabowska
A. Bobrowski
D. Drożyński
K. Kaczmarska
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Abstract

Moulding sands containing sodium silicate (water-glass) belong to the group of porous mixture with low resistance to increased humidity.

Thanks to hydrophilic properties of hardened or even overheated binder, possible is application of effective methods of hydrous

reclamation consisting in its secondary hydration. For the same reason (hydrophilia of the binder), moulds and foundry cores made of

high-silica moulding sands with sodium silicate are susceptible to the action of components of atmospheric air, including the contained

steam. This paper presents results of a research on the effect of (relative) humidity on mechanical and technological properties of

microwave-hardened moulding mixtures. Specimens of the moulding sand containing 1.5 wt% of sodium water-glass with module 2.5

were subjected, in a laboratory climatic chamber, to long-term action of steam contained in the chamber atmosphere. Concentration of

water in atmospheric air was stabilized for 28 days (672 h) according to the relative humidity parameter that was ca. 40%, 60% and 80% at

constant temperature 20 °C. In three cycles of the examinations, the specimens were taken out from the chamber every 7 days (168 h) and

their mechanical and technological parameters were determined. It was found on the grounds of laboratory measurements that moulds and

cores hardened with microwaves are susceptible to action of atmospheric air and presence of water (as steam) intensifies action of the air

components on glassy film of sodium silicate. Microwave-hardened moulding sands containing sodium silicate may be stored on a longterm

basis in strictly determined atmospheric conditions only, at reduced humidity. In spite of a negative effect of steam contained in the

air, the examined moulding mixtures maintain a part of their mechanical and technological properties, so the moulds and foundry cores

stored in specified, controlled conditions could be still used in manufacture.

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Authors and Affiliations

M. Stachowicz
K. Granat
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Abstract

In the paper, presented is a research on effectiveness of absorbing electromagnetic waves at frequency 2.45 GHz by unhardened moulding

sands prepared of three kinds of high-silica base and a selected grade of sodium silicate. Measurements of power loss of microwave

radiation (Pin) expressed by a total of absorbed power (Pabs), output power (Pout) and reflected power (Pref) were carried-out on a stand of

semiautomatic microwave slot line. Values of microwave power loss in the rectangular waveguide filled with unhardened moulding sands

served for determining effectiveness of microwave heating. Balance of microwave power loss is of technological and economical

importance for manufacture of high-quality casting moulds and cores of various shapes and sizes. It was found that relative density

influences parameters of power output and power reflected from samples of moulding sand placed in a waveguide. Absorption expressed

by the parameter Pabs is not related to granularity of high-silica base: fine, medium and coarse. It was found that the semiautomatic

microwave slot line supports evaluation of effectiveness of microwave absorption on the grounds of power loss measurements and enables

statistic description of influence of relative density of the sandmix on penetration of electromagnetic waves in unhardened moulding sands.

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Authors and Affiliations

M. Stachowicz
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Abstract

In this study, agar-based nanocomposite films containing ultra-porous silica aerogel particles were fabricated by gel casting using an aqueous agar/silica aerogel slurry. The silica aerogel particles did not show significant agglomeration and were homogeneously distributed in the agar matrix. Transmission electron microscopy observations demonstrated that the silica aerogel particles had a mesoporous microstructure and their pores were not incorporated into the agar polymer molecules. The thermal conductivities of the agar and agar/5 wt.% silica aerogel nanocomposite films were 0.36 and 0.20 W·m–1·K–1, respectively. The transmittance of the agar films did not decrease upon the addition of silica aerogel particles into them. This can be attributed to the anti-reflection effect of silica aerogel particles.

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Authors and Affiliations

Min-Jin Lee
Hyun-Ah Jung
Kyong-Jin Lee
Haejin Hwang
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Abstract

The study presented research on the possibility of using acoustic emission to detect and analyze the development of the alkali-silica reaction (ASR) in cement mortars. The experiment was conducted under laboratory conditions using mortars with reactive opal aggregate, accelerating the reaction by ensuring high humidity and temperature, in accordance with ASTM C227. The progress of corrosion processes was monitored continuously for 14 days. The tests were complemented with measurements of the expansion of the mortars and observations of microstructures under a scanning electron microscope. The high sensitivity of the acoustic emission method applied to material fracture caused by ASR enabled the detection of corrosion processes already on the first day of the test, much sooner than the first recorded changes in linear elongation of the specimens. Characteristic signal descriptors were analyzed to determine the progress of corrosion processes and indicate the source of the cracks. Analysis of recorded 13 AE parameters (counts total, counts to peak, duration, rise time, energy, signal strength, amplitude, RMS, ASL, relative energy, average frequency, initial frequency and reverberation frequency) indicates that the number of counts, signal strength and average frequency provide most information about the deleterious processes that occur in the reactive aggregate mortars. The values of RA (rise time/amplitude) and AF (average frequency) enabled the classification of detected signals as indicating tensile or shear cracks. The acoustic emission method was found suitable for monitoring the course of alkali-aggregate reaction effects.

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Authors and Affiliations

G. Świt
J. Zapała-Sławeta
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Abstract

Macroporous silica fibers having spherical cavities were fabricated by electrospinning using the spinning solution prepared from the mixed dispersion of tetraethylorthosilicate (TEOS) and polystyrene nanospheres as precursor and sacrificial templates, respectively, by injection through metallic nozzle. By applying electric field, the electro-spun fibers obtained by evaporation-driven self-assembly were collected on flat substrate or rotating drum, followed by the removal of the templates by calcination. The sound absorption coefficient of the porous fibers was measured by impedance tube, and the measured value was larger than 0.9 at high frequency region of incident waves. The surface of the resulting fibers was modified using fluorine-containing silane coupling agent to produce superhydrophobic fibrous materials to prevent the infiltration of humidity.

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Authors and Affiliations

Y.-S. Cho
H. Jin Lee
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Abstract

The effect of additives on the densification behavior and mechanical properties of pure and additive (Zr, B and Mg)-added silica ceramics were investigated for their application to the matrix phase of a silica fiber reinforced silica (SiO2/SiO2f) composite. The additives affected the rate of densification and crystallization (or transformation) of the amorphous silica. Among the compositions, pure silica ceramics sintered at 900°C for 1 h showed the maximum flexural strength. Based on the results, SiO2/SiO2f was fabricated by a repeated vacuum-assisted infiltration method followed by the heat treatment at 900°C for 1 h. The relative density of the composite was 78.2% with a flexural strength of 22.4 MPa. Fractography revealed that the composite was damaged by strong bonding at the fiber/matrix interface and the fracture of fiber.

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Authors and Affiliations

S.-Y. Ko
S.-M. Yong
S.J. Lee
D.-I. Cheong
S. Baek
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Abstract

The paper analyses the influence of chemical composition of silicone-based composites on their properties in the aspect of using them as long-term soft denture lining materials. Different concentrations of filler and methylhydrosiloxane-dimethylsiloxane copolymer were used. The filler was introduced into the composite with mechanical mixing combined with ultrasonic homogenization. Scanning electron microscopy was used to investigate the quality of filler dispersion. Shore A hardness, tensile strength, sorption, solubility and tensile bond strength to poly(methyl methacrylate) were measured. Tests show satisfactory results for some experimental composites, which met all the requirements for such materials.

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Authors and Affiliations

E. Jabłońska-Stencel
W. Pakieła
J. Żmudzki
J. Kasperski
G. Chladek
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Abstract

Odpady pogalwaniczne zaliczane są do odpadów niebezpiecznych. dlatego muszą być unieszkodliwiane. Jedną z najprostszych metod unieszkodliwiania jest zestalanie w spoiwach mineralnych. W niniejszej pracy przeprowadzono próby zestalania w zaprawie cementowej oraz w zaprawie cementowej z dodatkiem pyłów krzemionkowych odpadu powstałego po neutralizacji zużytych kąpieli do trawienia, rozcieńczonych wodami poplucznymi, pochodzącymi z procesu cynkowania oraz miedziowania drutu. Badania wykazały, że dodatek odpadów w ilości do 5% jest bezpieczny pod względem ekologicznym. Przy takiej ilości dodatku odpadów do cementu następuje nieznaczne obniżenie parametrów fizykomechanicznych, a metale są trwale irnmobilizowane w matrycy. Dodatek pyłów krzemionkowych w ilości 10% do cementu poprawiał cechy wytrzymałościowe wyrobów, ale wprowadzenie odpadów obniżało te parametry.
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Authors and Affiliations

Małgorzata Osińska
Agnieszka Ślosarczyk
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Abstract

The present study was conducted to evaluate the insecticidal efficiency and safety of zinc oxide nanoparticles (ZnO NPs) and hydrophilic silica nanoparticles (SiO2 NPs) against: adults of rice weevil (Sitophilus oryzae L.); red flour beetle (Tribolium castaneum Herbst.) and cowpea beetle (Callosobruchus maculatus F.) results showed that, both ZnO NPs and hydrophilic SiO2 NPs exhibited a significant toxic effect (df, F and p < 0.5) against S. oryzae and C. maculatus at the highest concentration while T. castaneum showed high resistance against the two tested materials. At the end of the experiment, recorded mortality was: 81.6, 98.3 and 58.3% at the highest concentration used for each insect (0.3, 2 and 8 gm ⋅ kg–1 of SNPs with C. maculatus, S. oryzae and T. castaneum, respectively), while mortality was 88.3, 100 and 38.3% at the highest concentration used for each insect (0.6, 2.5 and 8 gm ⋅ kg–1 of ZnO NPs with C. maculatus, S. oryzae and T. castaneum, respectively). Both tested materials caused high reductions in F1-progeny (%) with C. maculatus and S. oryzae. Histopathological examination of male mice livers showed hepatic architecture with congested blood sinusoids, binucleated hepatocytes nuclei, dilated central vein and margainated chromatin in some nuclei. Histopathological assessment of the lungs showed normal histoarchitecture. There were no differences in alveolar septa, bronchiolar and epithelium of the treated and untreated animals. Silica and zinc oxide nanoparticles have a good potential to be used as stored seed protectant alternatives if applied with proper safety precautions.

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Authors and Affiliations

Samia Ali Haroun
Mahmoud Elsaid Elnaggar
Doaa Mohamed Zein
Rehab Ibrahim Gad

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