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Number of results: 15
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Abstract

The annual rate of decomposition in five soil types of tundra situated in the Fugleberget drainage area (Hornsund Fjord, South Spitsbergen) was investigated by use of the method of standard cellulose samples. The rate of decomposition varied from 15% to over 65% a year and was closely connected with a contents of nitrogen in soil, amount of which varied from 0.33% to 3.44%. The results presently obtained are much higher than those obtained by the same method in other polar regions.

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Authors and Affiliations

Piotr Bieńkowski
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Abstract

The study was to determine the effect of water activity (0.850; 0.900; 0.950; 0.995; and 0.999 aw) on the growth of T. lanuginosus on solid media containing different cellulose substrates (crystalline cellulose, carboxymethyl cellulose - CMC, fi lter paper, and sawdust) and xylan. The growth of isolates from coffee beans and garden composts were compared. All isolates did not grow on media with aw < 0.950. On media with aw > 0.950, the hydrolysis zones were only observed on xylan and CMC. The highest daily growth and hydrolysis zone rates were mostly obtained at 0.995 aw and the lowest values were observed at 0.950 aw. The coffee beans isolates at 0.950 aw had the CMC hydrolysis coeffi cient 1.7-times higher than that for xylan. The fungal growth (FG) coeffi cient data indicate that the coffee beans isolates were able to utilize CMC and crystalline cellulose for growth and the highest growth rate was obtained at 0.999 aw. Subsequently, the compost isolates were able to grow on all substrates but the highest growth rate was obtained on CMC at 0.950 and 0.999 aw. Thus, coffee beans and composts provide T. lanuginosus isolates with various growth and hydrolytic zone rates in the range of 0.950−0.999 aw.
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Authors and Affiliations

Agata Markowska-Szczupak
Krzysztof Ulfig
Katarzyna Janda
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Abstract

This paper presents the findings of a study of gas emissivity and the volumetric gas flow rate from a patented modified cellulose mix used

in production of disposable sand casting moulds. The modified cellulose mix with such additives as expanded perlite, expanded

vermiculite and microspheres was used as the study material. The results for gas emissivity and the gas flow rate for the modified cellulose

mix were compared with the gas emissivity of the commercial material used in gating systems in disposable sand casting moulds. The

results have shown that the modified cellulose mix is characterized by a lower gas emissivity by as much as 50% and lower gas flow rate

per unit mass during the process of thermal degradation at the temperature of 900°C, compared to the commercial mix. It was also noted

that the amount of microspheres considerably affected the amount of gas produced.

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Authors and Affiliations

J. Sawicki
Z. Zawieja
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Abstract

The use of ammonium nitrate due to its high nitrogen content (> 26%) has made it the most utilized fertilizer in agricultural areas. However, being easily accessible with this feature encouraged its use for different purposes. Ammonium nitrate is usually produced with large tonnage (> 50 ton/h) and high cost (> $20 million) production processes. Therefore, any changes that can be made in the process must be applied in the process so that the result can be achieved easily without increasing the cost in any way. In this study, it is aimed to reduce the explosion sensitivity of ammonium nitrate used for explosive purposes in terrorist attacks. Thus, it was aimed to solve the problem by adding various chemicals to the ammonium nitrate production process so that it can only be used for agricultural purposes. For this purpose, the production process was examined by adding carboxymethyl cellulose and polyethylene glycol to the ammonium nitrate production process and the accuracy of the results was tested by instrumental analysis methods.

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Authors and Affiliations

Ahmet Ozan Gezerman
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Abstract

The study investigates the effect of the organic compound representing the cellulose derivative - sodium salt of carboxymethyl cellulose (CMC/Na) on the structure of the main component of bentonite (B) - montmorillonite (MMT). Structural analysis revealed that the CMC/Na of different viscosity interacts with the mineral only via surface adsorption, causing at the same time partial or full delamination of its layered structure. This was confirmed by the XRD diffraction tests. Such polymer destructive influence on the structure of the modified main component of the bentonite limits the use of its composites as an independent binder in moulding sand technology, but does not exclude it from acting as an additive being a lustrous carbon carrier. According to the IR spectra of the B/CMC/Na materials, it can be stated that the interaction between the organic and inorganic parts is based on the formation of hydrogen bonds. That kind of the interpretation applies especially to the MMT modified in the bentonite with a lower viscosity polymer. The characteristics of the main IR absorption bands for composites with a higher viscosity polymer indicates the formation of less stable structures suggesting the random nature of the hydrogen bonds formation.

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Authors and Affiliations

S. Cukrowicz
B. Grabowska
K. Kaczmarska
A. Bobrowski
M. Sitarz
B. Tyliszczak
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Abstract

Results for microcrystalline cellulose pyrolysis are presented, which includes thermogravimetric measurements and kinetic analysis of experimental data. The effect of sample mass size and heating rate on estimated values of activation energy and pre-exponential factor is demonstrated and a simple modification of procedure is proposed that allows for the correct values of kinetic parameters regardless of the experimental conditions. The efficiency of the proposed method is confirmed for two endothermic chemical reactions. A method of nonlinear regression is used for calculation of kinetic parameters for a single or TG curve or several curves simultaneously.

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Authors and Affiliations

Lech Nowicki
Maciej Markowski
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Abstract

The paper includes the TG-DTG thermogravimetric air-testing of a cellulose mixture modified with the additives of expanded vermiculite or expanded perlite. A thermal degradation test was carried out at 1000°C with a simultaneous qualitative analysis of the emitted gases. During the thermal degradation process, the thermal effects were also measured. The research results indicate that expanded vermiculite or expanded perlite do not emit toxic gases during thermal degradation. The cellulose mixture modification, with the additives of expanded vermiculite or perlite, does not result in the creation of new gaseous compounds in the process of thermal degradation. A s investigated below, the mixtures tested in this article find application in gating systems for supplying liquid metal in no-bake moulds. Such cellulose-based material solutions shall allow the foundry industry to introduce less gas vaporising technologies within the entire casting production process.

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Authors and Affiliations

Z. Zawieja
J. Sawicki
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Abstract

The biodiversity of aqueous environments has been affected due to the disposal of wastewater highly contaminated with heavy metal ions, causing much damage to ecosystems. These pollutants are very toxic and bioaccumulate in living organisms. This work attempts to evaluate the adsorption of nickel ad cadmium ions using three biomasses from agricultur-al residues (corn cob – CC, orange peel – OP, and oil palm bagasse – PB) modified with alumina nanoparticles. The bio-masses were characterized via compositional analysis and a point of zero charges to quantify the presence of lignin, cellu-lose, hemicellulose, and the feasible pH, taking advantage of the biomass charge. After modification with Al2O3 nanoparti-cles. The resulting adsorbents were characterized via FT-IR analysis to identify the functional groups that most contributed to the adsorption performance. Furthermore, the influence of Al2O3 nanoparticles was analysed on the adsorption capacities of the evaluated biomasses using batch systems at a temperature of 25°C and pH 6. All biomasses displayed a high content of cellulose, estimating a weight percentage of about 19.9%, 14.3%, and 13.1% for PB, OP, and CC samples, respectively. The FT-IR spectrum confirmed hydroxyl and carboxyl functional groups, which contribute to enhancing the adsorption capacities of the modified biomasses. Functional adsorption capacity was observed for all biomasses after modification with Al2O3 nanoparticles, achieving at pH 6.0 a cadmium removal from 92% (CC-Al2O3 and PB-Al2O3) up to 95.8±0.3% (OP-Al2O3). In nickel ions, it was estimated a broader adsorption capacity at pH 6.0 of about 86±0.4% after using the CC-Al2O3 sample, 88±0.1% for the PB-Al2O3 adsorbent, and 98±0.2% for the OP-Al2O3 sample, confirming the suitability of these Al2O3-modified biomasses for the removal of heavy metal ions.
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Authors and Affiliations

Adriana Herrera-Barros
1
ORCID: ORCID
Candelaria Tejada-Tovar
1
ORCID: ORCID
Angel D. Gonzalez-Delgado
1
ORCID: ORCID

  1. University of Cartagena, Avenida del Consulado Calle 30 No. 48-152, Cartagena, Bolívar, Colombia
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Abstract

In this study, a new chemically modified cellulose polymer-capped ZnO nanopowder prepared by hydrothermal method using chemically modified cellulose polymer as capping agent was successfully reported. The structural characteristics of CMC-capped ZnO nanopowder was reported by FTIR, XRD, SEM and EDX studies. XRD results revealed crystallographic properties like crystal composition, phase purity and crystallite size of the prepared CMC-capped ZnO nanopowder and average size calculated by Debye Scherrer formula as 14.66 nm. EDX studies revealed that the presence of elemental compositions of capping agent in the nanopowder samples. The optical characterization of the CMC-capped ZnO nanopowder was studied using UV absorption (λmax = 303 nm) and PL spectroscopy (λex = 295 nm). The average crystal diameter and grain size were calculated by effective mass approximation formula and compared with XRD findings that agreed well and verified CMC capped ZnO with particle size of 193 nm. Thus, the promising optical characteristics shown by the synthesized CMC capped ZnO nanopowders exposes its potential usage in bio-medical fields.
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Bibliography

[1] M. Abbas, M. Buntinx, W. Deferme, R. Peeters, Nanomaterials 9 (10), 1494 (2019). DOI: https://doi.org/10.3390/nano9101494
[2] J. Chen, Q. Yu, X. Cui, M. Dong, J. Zhang, C. Wang, J. Fan, Y. Zhu, Z. Guo, J. Mater. Chem. C 7 (38), 11710-11730 (2019). DOI: https://doi.org/10.1039/c9tc03655e
[3] S. Huda, M.A. Alam, P.K. Sharma, J. Drug Deliv. Sci. Technol. 102018 (2020). DOI: https://doi.org/10.1016/j.jddst.2020.102018
[4] F. Farjadian, A.R. Akbarizadeh, L. Tayebi, Heliyon 6 (8), e04747 (2020). DOI: https://doi.org/10.1016/j.heliyon.2020.e04747
[5] M.M. Abutalib, A. Rajeh, Polym. Test. 106803 (2020). DOI: https://doi.org/10.1016/j.polymertesting.2020.106803
[6] L. Cen, K.G. Neoh, E T. Kang, Langmuir 19 (24), 10295-10303 (2003). DOI: https://doi.org/10.1021/la035104c
[7] L. Muthulakshmi, A. Varada Rajalu, G.S. Kaliaraj, S. Siengchin, J. Parameswaranpillai, R. Saraswathi, Composites Part B: Engineering, 175, 107177 (2019). DOI: https://doi.org/10.1016/j.compositesb. 2019.107177
[8] M.V. Lungu, E. Vasile, M. Lucaci, D. Pătroi, N. Mihăilescu, F. Grigore, V. Marinescu, A. Brătulescu, S. Mitrea, A. Sobetkii, A.A. Sobetkii, M. Popa, M.C. Chifiriuc, Materials Characterization 120, 69-81 (2016). DOI: https://doi.org/10.1016/j.matchar.2016.08.022
[9] Zhao, Si-Wei, Guo, Chong-Rui, Hu, Ying-Zhu, Guo, Yuan-Ru, Pan, Qing-Jiang. Open Chemistry 16 (1), 9-20 (2018). DOI: https://doi.org/10.1515/chem-2018-0006
[10] R. Saravanan, L. Ravikumar, Water Environ. Res. 89 (7), 629-640 (2017). DOI: https://doi.org/10.2175/106143016X14733681696329
[11] J. Wang, S. Yu, H. Zhang, Optik 180, 20-26 (2019). DOI: https://doi.org/10.1016/j.ijleo.2018.11.062
[12] R. Saravanan, L. Ravikumar, J. Water Resour. Prot. 7 (6), 530 (2015). DOI: https://doi.org/10.4236/jwarp.2015.76042
[13] S. Krishnaswamy, P. Panigrahi, S. Kumaar, G.S. Nagarajan, Nano- Struct. Nano-Objects 22, 100446 (2020). DOI: https://doi.org/10.1016/j.nanoso.2020.100446
[14] C. Miao, W.Y. Hamad, Curr. Opin. Solid State Mater. Sci. 23 (4), 100761 (2019). DOI: https://doi.org/10.1016/j.cossms.2019.06.005
[15] K.I. Aly, O. Younis, M.H. Mahross, O. Tsutsumi, M.G. Mohamed, M.M. Sayed, Polym. J. 51 (1), 77-90 (2019). DOI: https://doi.org/10.1038/s41428-018-0119-6
[16] K. Rojas, D. Canales, N. Amigo, L. Montoille, A. Cament, L.M. Rivas, O. Gil-Castell, P. Reyes, M.T. Ulloa, A. Ribes-Greus, Compos. Part B Eng. 172, 173-178 (2019). DOI: https://doi.org/10.1016/j.compositesb.2019.05.054
[17] S. Amjadi, S. Emaminia, S.H. Davudian, S. Pourmohammad, H. Hamishehkar, L. Roufegarinejad, Carbohydr. Polym. 216, 376- 384 (2019). DOI: https://doi.org/10.1016/j.carbpol.2019.03.062
[18] D. Bharathi, R. Ranjithkumar, B. Chandarshekar, V. Bhuvaneshwari, Int. J. Biol. Macromol. 129, 989-996 (2019). DOI: https://doi.org/10.1016/j.ijbiomac.2019.02.061
[19] K. Rajesh, V. Crasta, N.R. Kumar, G. Shetty, P.D. Rekha, J. Polym. Res. 26 (4), 99 (2019). DOI: https://doi.org/10.1007/s10965-019-1762-0
[20] Y. Yang, W. Guo, X. Wang, Z. Wang, J. Qi, Y. Zhang, Nano letters, 12 (4), 1919-1922 (2012). DOI: https://doi.org/10.1021/nl204353t
[21] Z. R. Khan, M. Arif , A. Singh, International Nano Letters, 2, 22 (2012). DOI: https://doi.org/10.1186/2228-5326-2-22
[22] F. Rodríguez-Mas, J.C. Ferrer, J.L. Alonso, D. Valiente, S. Fernández de Ávila, Crystals 10 (3), 226 (2020). DOI: https://doi.org/10.3390/cryst10030226
[23] S.K. Ali, H. Wani, C. Upadhyay, K.S. Madhur, I. Khan, S. Gul, N. Jahan, F. Ali, S. Hussain, K. Azmi, Indones. Phys. Rev. 3 (3), 100-110 (2020). DOI: https://doi.org/10.29303/ipr.v3i3.64
[24] D. Ponnamma, J.-J. Cabibihan, M. Rajan, S.S. Pethaiah, K. Deshmukh, J.P. Gogoi, S.K. Pasha, M.B. Ahamed, J. Krishnegowda, B.N. Chandrashekar, Mater. Sci. Eng. C 98, 1210-1240 (2019). DOI: https://doi.org/10.1016/j.msec.2019.01.081
[25] J. Loste, J.-M. Lopez-Cuesta, L. Billon, H. Garay, M. Save, Prog. Polym. Sci. 89, 133-158 (2019). DOI: https://doi.org/10.1016/j.progpolymsci.2018.10.003
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Authors and Affiliations

R. Jagadeeswari
1
P. Selvakumar
2
ORCID: ORCID
V. Jeevanantham
2
ORCID: ORCID
R. Saravanan
1

  1. Department of Chemistry, KPR Institute of Engineering And Technology, Coimbatore-641407, Tamilnadu, India
  2. Department of Chemistry, Vivekanandha College of Arts And Sciences for Women, Tiruchengode-637205, Tamilnadu, India
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Abstract

The fiber-cement and cellulose boards are materials commonly used in architectural engineering for exterior and interior applications such as building facades or as wall and roof covering materials. The aim of the study was to present the ultrasonic non-contact method of testing fiber-cement boards with Lamb waves and to discuss the results and limitations of the method in context of quality control of the material. The experiments were performed for the corrugated boards using a laboratory non-contact ultrasonic scanner. Lamb waves were generated in the tested materials by a transmitter excited by a chirp signal with a linearly modulated frequency. Waves transmitted through the tested material are acquired by the receiver and registered by the PC based acquisition system. The tests were done on reference plate board and the corrugated boards. As the main descriptor to assess the quality of tested boards the maximum amplitude of transmitted Lamb waves was selected. The significant role of boundary effects and frequency of waves was noticed. The obtained results have confirmed the usefulness of the applied ultrasonic method for testing macroscopic inhomogeneity of corrugated fiber-cement boards.
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Bibliography

  1.  Z. Su, L. Ye, and Y. Lu, “Guided Lamb waves for identification of damage in composite structures: A review”, J. Sound Vibr. 295, 753–780 (2006).
  2.  J.K. Agrahari and S. Kapuria, “Effects of adhesive, host plate, transducer and excitation parameters on time reversibility of ultrasonic Lamb waves”, Ultrasonics 70, 147–157 (2016).
  3.  R. Kędra and M. Rucka, “Preload monitoring in a bolted joint using Lamb wave energy”, Bull. Pol. Acad. Sci. Tech. Sci. 67(6), 1161–1169 (2019).
  4.  S. Vázquez, J. Gosálbez, I. Bosch, A. Carrión, C. Gallardo, and J. Payá, “Comparative Study of Coupling Techniques in Lamb Wave Testing of Metallic and Cementitious Plates”, Sensors (Basel) 19(19), 4068 (2019).
  5.  L. Yu, Z. Tian, and C.A.C. Leckey, “Crack imaging and quantification in aluminum plates with guided wave wavenumber analysis methods”, Ultrasonics 62, 203–212 (2015).
  6.  M. Radzieński, P. Kudela, W. Ostachowicz, P. Bolimowski, R. Kozera, and A. Boczkowska, “Lamb-wave-based method in the evaluation of self-healing efficiency”, Appl. Sci. 10, 2585 (2020).
  7.  K. Imielińska, M. Castaingsc, R. Wojtyrab, J. Harasa, E. Le Clezioc, and B. Hosten, “Air-coupled ultrasonic C-scan technique in impact response testing of carbon fibre and hybrid: glass, carbon and Kevlar/epoxy composites”, J. Mat. Process. Techn. 157–158, 513–522 (2004).
  8.  H.B. Kichou, J.A. Chavez, A. Turo, J. Salazar, and M.J. Garcia-Hernandez, “Lamb waves beam deviation due to small inclination of the test structure in air-coupled ultrasonic NDT”, Ultrasonics 44, e1077–e1082 (2006).
  9.  S. Yashiro, J. Takatsubo, and N. Toyama, “An NDT technique for composite structures using visualized Lamb-wave propagation”, Compos. Sci. Technol. 67, 3202–3208 (2007).
  10.  Ł. Ambrozinski, B. Piwakowski, T. Stepinski, and T. Uhl, “Application of air-coupled ultrasonic transducers for damage assessment of composite panels”, 6th European Workshop on Structural Health Monitoring, 2014, pp. 1‒8.
  11.  R. Drelich, T. Gorzelańczyk, M. Pakuła, and K. Schabowicz, “Automated control of cellulose fibre cement boards with a non-contact ultrasound scanner”, Autom. Constr. 57, 55–63 (2015).
  12.  M.S. Harb and F.G. Yuan, “Non-contact ultrasonic technique for Lamb wave characterization in composite plates”, Ultrasonics 64, 162–169 (2016).
  13.  S. Talberg and T.F. Johansen, “Acoustic measurements above a plate carrying Lamb waves”, Proceedings of the 39th Scandinavian Symposium on Physical Acoustics, Geilo, Norway, 2016.
  14.  T. Marhenke, J. Neuenschwander, R. Furrer, J. Twiefel, J. Hasener, P. Niemz, and S.J. Sanabria, “Modeling of delamination detection utilizing air-coupled ultrasound in wood-based composites”, NDT E Int. 99, 1–12 (2018).
  15.  K.J. Vössing, M. Gaal, and E. Niederleithinger, “Air-coupled ferroelectret ultrasonic transducers for nondestructive testing of wood- based materials”, Wood Sci. Technol. 6, 1527–1538 (2018).
  16.  N. Toyama, J. Ye, W. Kokuyama, and S. Yashiro, “Non-contact ultrasonic inspection of impact damage in composite laminates by visualization of lamb wave propagation”, Appl. Sci. 9, 46 (2019).
  17.  A. Römmeler, P. Zolliker, J. Neuenschwander, V. van Gemmeren, M. Weder, and J. Dual,“Air coupled ultrasonic inspection with Lamb waves in plates showing mode conversion”, Ultrasonic 100, 105984 (2020).
  18.  M. Kaczmarek, B. Piwakowski, and R. Drelich, “Noncontact ultrasonic nondestructive techniques: state of the art and their use in civil engineering”, J. Infrastruct. Syst. 23(1), 45–56an (2017).
  19.  B. Yilmaz, A. Asokkumar, E. Jasiuniene, and R. J. Kazys, “Air-coupled, contact, and immersion ultrasonic non-destructive testing: Comparison for bonding quality evaluation”, Appl. Sci. 10, 6757 (2020).
  20.  J. Liu and N.F. Declerq, “Ultrasonic geometrical characterization of periodically corrugated surfaces”, Ultrasonics 53, 853–861 (2013).
  21.  J.D. Achenbach, Wave propagation in elastic solids, North-Holland Publishing Company, Amsterdam, 1973.
  22.  O. Abraham, B. Piwakowski, G. Villain, and O. Durand, “Non-contact, automated surface wave measurements for the mechanical characterization of concrete”, Constr. Build. Mater. 37, 904–915 (2012).
  23.  R. Drelich, B. Piwakowski, and M. Kaczmarek, “Identification of inhomogeneous cover layer by non-contact ultrasonic method – studies for model materials”, Annales du Bâtiment et des Travaux Publics 66(1–3), 47–52 (2014).
  24.  Ł. Amboziński, B. Piwakowski, T. Stepinski, and T. Uhl, “Evaluation of dispersion characteristics of multimodal guided waves using slant stack transform”, NDT E Int. 68, 88–97 (2014).
  25.  W. Ke, M. Castaings, and C. Bacon, “3D finite element simulations of an air-coupled ultrasonic NDT system”, NDT E Int. 42, 524–533 (2009).
  26.  A. Piekarczuk, “Test-supported numerical analysis for evaluation of the load capacity of thin-walled corrugated profiles”, Bull. Pol. Acad. Sci. Tech. Sci. 65(6), 791‒798 (2017).
  27.  M. Cieszko, R. Drelich, and M. Pakuła, “Wave dispersion in randomly layered materials”, Wave Motion 64, 52–67 (2016).
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Authors and Affiliations

Radosław Drelich
1
ORCID: ORCID
Michał Rosiak
1
Michał Pakula
1
ORCID: ORCID

  1. Faculty of Mechatronics, Kazimierz Wielki University, Kopernika 1, 85-074 Bydgoszcz, Poland
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Abstract

Quenching technology requires the use of media with different cooling intensities and various shapes of cooling curves that show different particularities compared to that of conventional media such as water, oil, or emulsions. The use of synthetic quenching media is relatively new and also has multiple advantages such as non-flammability, safety in use and low cost. In this study, the cooling media tested was obtained by mixing 2 wt% carboxymethyl cellulose with 2 wt% NaOH in one litter of water. Moreover, three different temperatures (20°C, 40°C and 60°C) of the quenching media were evaluated. By dissolution in water, a synthetic solution with low viscosity, surfactant and lubricant was obtained. Because carboxymethyl cellulose is a biodegradable organic material, that is obtained as a by-product in the manufacture of paper, a basic substance with a preservative effect was added. According to this study, both the variation diagram of the heat transfer coefficient and the diagram of the cooling rates, during the cooling stages give important indications regarding the use of a liquid cooling medium for quenching.
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Authors and Affiliations

M.C. Perju
1
ORCID: ORCID
C. Nejneru
1
ORCID: ORCID
D.D. Burduhos-Nergis
1 2
ORCID: ORCID
P. Vizureanu
1 2
ORCID: ORCID
M.G. Minciuna
1
ORCID: ORCID
A.V. Sandu
1 2
ORCID: ORCID

  1. “Gheorghe Asachi” Technical University of Iasi, Faculty of Materials Science and Engineering, Prof. D. Mangeron Street, No. 41, 700050, Iasi, Romania
  2. Romanian Inventors Forum, Sf. P. Movila 3, Iasi, Romania
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Abstract

The parenchyma cellulose isolated from bagasse pith was used as an alternative resource for preparation of water-soluble cellouronic acid sodium salt (CAS). The influence of ultrasound treatment on the cellulose was investigated for obtaining CAS by regioselective oxidization using 4-acetamide-TEMPO and NaClO with NaClO2 as a primary oxidant in an aqueous buffer at pH 6.0. The yield, carboxylate content and polymerization degree (DP) of CAS were measured as a function of ultrasonic power, agitating time and cellulose consistency by an orthogonal test. The ultrasound-treated conditions were further improved by discussion of ultrasonic power, the most important factor influencing the yield and DP. An optimized CAS yield of 72.9% with DP value (DPv) of 212 was found when the ultrasonic strength is 550 W, agitating time is 3 h and cellulose consistency is 2.0%. The oxidation reactivity of cellulose was improved by ultrasonic irradiation, whereas no significant changes in crystallinity of cellulose were measured after ultrasonic treatment. Moreover, the ultrasound treatment has a greater effect on yielding CAS from parenchyma cellulose than from bagasse fibrous' one. The CAS was further characterized by Fourier transform infrared spectroscopy (FT-IR) and Scanning electron microscopy (SEM).

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Authors and Affiliations

Xin Gao
Keli Chen
Heng Zhang
Lincai Peng
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Abstract

The herein paper contains the results of investigations on a new type of cellulose blend used for the manufacture of profiles applied in the

process of making gating systems in the foundry industry. A standard cellulose profile was subjected to an experiment. During the

experiment the profile was filled with a liquid cast iron and at the same time the temperatures of the liquid metal crystallizing inside the

profile were measured as well as the temperature of the outer layer of the profile was controlled. Further, the microstructure of the cast

iron, which crystallized out inside the cellulose profile, was analysed and the cellulose, thermally degraded after the experiment, was

verified with the use of the chemical analysis method. Moreover, a quality analysis of the original as well as the degraded cellulose profile

was run with the use of the FTIR infrared spectroscopy. The presented results revealed that the cellulose blend is aluminium silicate

enriched and contains organic binder additives. The cast iron, which crystallized out, tended to have an equilibrium pearlitic structure with

the release of graphite and carbides. The generation of disequilibrium ausferrite phases was also observed in the structure.

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Authors and Affiliations

J. Sawicki
G. Gumienny
Z. Zawieja
A. Sobczyk-Guzenda
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Abstract

The content of structural carbohydrates and lignin are important assessment criteria of the feed value of meadow plants. It is affected by many independent factors, including among others its development stage during the harvest as well as climatic conditions, especially the amount of rainfall. During the years 2014–2016, plant samples were harvested at weekly intervals, respectively five times from late April to late May. The effect of harvest date on cellulose, hemicelluloses and lignin contents was evaluated. The chemical composition of plants was varied, depending not only on harvest date but also on the year of study. Regardless of the course of meteorological conditions in subsequent growing seasons, the increase of cellulose (from 236.5 to 297.9 g∙kg–1 DM), hemicelluloses (from 159.3 to 210.8 g∙kg–1 DM), and lignin (from 31.5 to 43.1 g∙kg–1 DM) in the following dates of harvest were observed. These parameters were also positively correlated with the total rainfall from the begging of vegetation season to the date of plants sampling (R2 = 0.65, 0.12 and 0.44 for cellulose, hemicelluloses and lignin, respectively), and with the average daily air temperature in the moment of harvest (R2 = 0.66, 0.32 and 0.52 for cellulose, hemicelluloses and lignin, respectively). The cellulose and lignin content, regardless of the harvest date, were significantly higher in the first year of the study (2014), when moisture conditions for plant development were optimal.
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Authors and Affiliations

Barbara Wróbel
1
ORCID: ORCID
Waldemar Zielewicz
2
ORCID: ORCID
Anna Paszkiewicz-Jasińska
1
ORCID: ORCID
Bartosz Spychalski
1
Zuzanna Jakubowska
1

  1. Institute of Technology and Life Sciences – National Research Institute, Falenty, al. Hrabska 3, 05-090 Raszyn, Poland
  2. Poznań University of Life Sciences, Department of Grassland and Natural Landscape Sciences, Poznań, Poland
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Abstract

All over the world, highway traffic is increasing rapidly, as is the population and the road network. The country’s maximum and minimum temperatures also vary greatly. Moreover, the pavements are subjected to various types of damage. Pavement binders and mixtures are a constant area of research and development for scientists and engineers. Adding fibers to bituminous mixes may improve the properties of fatigue and strength of the material. Natural fibers may be used to improve asphalt mixtures performance due to their inherent compatibility with asphalt cement and excellent mechanical properties. Also, the high stone content and relatively high asphalt content in SMA mixture led to the occurrence of drain-down of the asphalt mastic from the mixture, and this problem requires the use of stabilizing additives such as cellulose fibers, mineral fibers, or polymers to mitigate this problem and ensure long-term performance. The most public sort of stabilizing additives is cellulose fiber. Overall, natural fibers in stone mastic asphalt mixes are discussed in this paper. An additional focus is on how asphalt concrete will be affected by natural fibers, mixing techniques, and managerial decisions. According to the review, the stabilizing and strengthening impact of natural fibers on the performance of asphalt mixes have been extensively researched. Natural fibers can significantly increase the rut and flow resistance of asphalt mixtures. Adding natural fibers to pavement can increase structural resistance to pavement distress.
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Authors and Affiliations

Israa AlSaadi
1
ORCID: ORCID
Sady A. Tayh
2
ORCID: ORCID
Abbas F. Jasim
2
ORCID: ORCID
Rana Yousif
2
ORCID: ORCID

  1. University of Baghdad, Department of Construction and Projects, Baghdad
  2. University, College of Engineering, Highways, and Transportation Engineering Department, Baghdad, Iraq

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