Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 3
items per page: 25 50 75
Sort by:
Download PDF Download RIS Download Bibtex

Abstract

Many precision devices, especially measuring devices, must maintain their technical parameters in variable ambient conditions, particularly at varying temperatures. Examples of such devices may be super precise balances that must keep stability and accuracy of the readings in varying ambient temperatures. Due to that fact, there is a problem of measuring the impact of temperature changes, mainly on geometrical dimensions of fundamental constructional elements of these devices. In the paper a new system for measuring micro-displacements of chosen points of a constructional element of balance with a resolution of single nanometres and accuracy at a level of fractions of micrometres has been proposed.

Go to article

Authors and Affiliations

Marek Dobosz
Adam Woźniak
Mariusz Kożuchowski
Marek Ściuba
Olga Iwasińska-Kowalska
Download PDF Download RIS Download Bibtex

Abstract

Casting industry has been enriched with the processes of mechanization and automation in production. They offer both better working standards, faster and more accurate production, but also have begun to generate new opportunities for new foundry defects. This work discusses the disadvantages of processes that can occur, to a limited extend, in the technologies associated with mould assembly and during the initial stages of pouring. These defects will be described in detail in the further part of the paper and are mainly related to the quality of foundry cores, therefore the discussion of these issues will mainly concern core moulding sands. Four different types of moulding mixtures were used in the research, representing the most popular chemically bonded moulding sands used in foundry practise. The main focus of this article is the analysis of the influence of the binder type on mechanical and thermal deformation in moulding sands.
Go to article

Authors and Affiliations

A. Grabarczyk
1
ORCID: ORCID
K. Major-Gabryś
1
ORCID: ORCID
J. Jakubski
1
ORCID: ORCID
St.M. Dobosz
1
ORCID: ORCID
D. Bolibruchová
2
ORCID: ORCID
R. Pastirčák
2
ORCID: ORCID

  1. AGH University of Science and Technology, Faculty of Foundry Engineering, Department of Moulding Materials, Mould Technology and Foundry of Non-ferrous Metals, Al. Mickiewicza 30, 30-059 Krakow, Poland
  2. University of Zilina, Žilinská Univerzita v Žiline, Faculty of Mechanical Engineering, Žilina, Slovak Republic
Download PDF Download RIS Download Bibtex

Abstract

Biocompatibility, biodegradability and non-toxicity are the main attributes of any material to be used in biomedical applications. Among all the potential stimuli, pH, salt and temperature exist naturally in the internal environment of the human body. Hence internal stimuli responsive hydrogels can be exploited for specific drug delivery and tissue replacement. Poly(vinyl alcohol) (PVA) is the world’s largest volume synthetic polymer, produced for its excellent chemical resistance, physical properties and complete biodegradability, which has resulted in broad practical applications. PVA could be considered a suitable host material due to its good thermo-stability, chemical resistance and film-forming ability. It is also an important material because of its large-scale applications. Novel data analysis techniques were developed to analyze the response of PVA to external stimuli, including temperature and/or pH. The presented non-contact method shows that the PVA polymer gel, physically cross-linked by freezing and thawing, shrinks and swells under the influence of temperature, which is a reversible phenomenon. Under the given conditions, such as temperature, pH and mechanical load, the dominant factor affecting the swelling or contraction of the hydrogel is the change in the temperature of the liquid in which the PVA hydrogel sample is immersed.
Go to article

Bibliography

  1.  C. Heras Alarcon, S. Pennadam, and C. Alexander, “Stimuli responsive polymers for biomedical applications”, Chem. Soc. Rev. 34, 276‒285 (2005).
  2.  P. Siriphannon and Y. Iamphaojeen, “Facile synthesis of chitosan/CuO nanocomposites for potential use as biocontrol agents”, Bull. Pol. Acad. Sci. Tech. Sci. 66(3), 311‒316 (2018).
  3.  N.A. Peppas, Y. Huang, M.A. Torres-Lugo, J.H. Ward, and J. Zhang, “Physicochemical foundations and structural design of hydrogels in medicine and biology”, Ann. Rev. Biomed. Eng. 9, 2–29 (2000).
  4.  F. Eeckman, K. Amighi, and A.J. Moes, “Effect of some physiological and non-physiological compounds on the phase transition temperature of thermoresponsive polymer intended for oral controlled drug delivery”, Int. J. Pharm. 222, 259‒270 (2001).
  5.  I. Hager, “Behaviour of cement concrete at high temperature”, Bull. Pol. Acad. Sci. Tech. Sci. 61(1), 145–154 (2013).
  6.  P. Lee, E. Cobain, J. Huard, and L. Huang, “Thermo sensitive hydrogel PEG-PLGA-PEG enhances engraftment of muscle-derived stem cell and promotes healing in diabetic wound”, Mol. Ther. 15(6), 1189‒1194 (2007).
  7.  Y. Qiu and K. Park, “Environment-sensitive hydrogels for drug delivery”, Drug Deliver. Rev. 53, 321‒339 (2001).
  8.  H. Muta, M. Miwa, and M. Satoh, “Ion-specific swelling of hydrophilic polymer gels”, Polymer 42, 6313–6316 (2001).
  9.  Y. Masuda, T. Tanaka, and T. Nakanishi, “Ion-specific swelling behavior of poly(vinyl alcohol) gel prepared by γ-ray irradiation”, Colloid. Polym. Sci. 279, 1241–1244 (2001).
  10.  K. Kazimierska-Drobny and M. Kaczmarek, “Identification of diffusive transport properties of poly(vinyl alcohol) hydrogels from reservoir test”, Mater. Sci. Eng. C. 33, 4533–4538 (2013).
  11.  K. Kazimierska-Drobny and M. Kaczmarek, ”Effect of NaCl and KCl solutions on deformation of PVA hydrogel – chemo-mechanical coupling” (in English), Polimery 1 (44) (2020).
  12.  W. Herrera-Kao, and W. Aquilar-Vega, “Storage modulus changes with temperature in poly(vinyl alcohol), PVA/poly(acrylic acid) PAA, blends”, Polym. Bull. 24, 449‒456 (1999).
  13.  H. Yamamoto, N. Heyamoto, T. Matsui, N. Nurayama, and J. Shibata, ”Volumetric change and surface properties of temperature-sensitive polyvinylalcohol (PVA) hydrogel”, Int. J. Thermophys. 24(5), 1385–1394 (2003).
  14.  O.W. Guirguis and M. Modelhey, “Thermal and structural studies of poly(vinyl alcohol) and hydroxypropyl cellulose blends”, Nat. Sci. 4(1), 57‒67 (2012).
  15.  Y. Liu, L. Geever, J.E. Kennedy, C.L. Higginbotham, P.A. Cahill, and G.B. McGuinness, “Thermal behavior and mechanical properties of physically crosslinked PVA/Gelatin hydrogels”, J. Mech. Behav. Biomed. Mater. 3, 203‒209 (2010).
  16.  B. Wang, M. Liu, Z. Chen, R. Liang, S. Ding, S. Chen, and S. Jin, “Preparation, characterization and controlled release investigation of interpenetrating polymer networks of poly(acrylic acid)/triazole modified poly(vinyl alcohol)”, Int. J. Pharm. 331, 19‒26 (2007).
  17.  F. Jiangi and G. Lixia, “PVA/PAA thermo-crosslinking hydrogel fiber: preparation and pH-sensitive properties in an electrolyte solution”, Eur. Polym. J. 38, 1653‒1658 (2002).
  18.  S.J. Kim, S.G. Yoon, S.L. Lee, S.H. Lee, and S.I. Kim, “Electrical Sensitivity Behavior of a Hydrogel Composed of Polymethacrylic Acid/Poly(vinyl alcohol)”, J. Appl. Polym. 91, 3613‒3612 (2004).
  19.  J. Lu, Y. Li, D. Hu, X. Chen, Y. Liu, L. Wang, and Y. Zhao, “Synthesis and properties of pH-, thermos-, and salt-sensitive modified poly(aspartic acid)/poly(vinyl alcohol) IPN hydrogel and its drug controlled release”, BioMed Res. Int. 2015, 1‒12 (2015).
  20.  P. Guo, J. Liang, Y. Li, H. Fu, H. Jing, S. Guan, D. Han, and L. Niu, “High strength and pH-responsive self-healing poly(vinyl alcohol/ poly 6-acrylamidohexanoic acid hydrogel based on dual physically cross-linked network”, Colloids Surf. A. 571, 64‒71 (2019).
  21.  Q. Zhang, L. Liu, H. Zhou, X. Wu, and K.D. Yao, “pH-responsive swelling behavior of collagen complex materials”, Artif. Cells Nanomed. Biotechnol. 28(3), 255‒262 (2000).
  22.  R. Morita, R. Honda, and Y. Takahashi, “Development of oral controlled release preparations, a PVA swelling controlled release system (SCRS). I. Design of SCRS and its release controlling factor”, J. Control Release 63, 297‒304 (2000).
  23.  M. El Fray, A. Pilaszkiewicz, W. Święszkowski, and K. Kurzydlowski, “Chemically and physically crosslinked poly(vinyl alcohol) hydrogels for cartilage repair”, E-Polymer. P-013, 1–6 (2005).
  24.  M. Liu, H. Su, and T. Tan,” Synthesis and properties of a thermos- and pH-sensitive poly(N-isopropyl acrylamide)/polyaspartic acid IPN hydrogels”, Carbohyd. Polym. 87, 2425‒2431 (2012).
  25.  H. Byun, B. Hong, S.Y. Nam, and S.Y. Jung, “Swelling Behavior and Drug Release of Poly(vinyl alcohol) Hydrogel Cross-Linked with Poly(acrylic acid)”, Macromol. Res. 16(3), 189‒193 (2008).
  26.  M. Rizwan, R. Yahya, Z. Hassan, and M. Azzahari, ”pH sensitive hydrogels in drug delivery: Brief history, properties, swelling, and release mechanism, material selection and applications”, Polymers 9, 137 (2017).
  27.  M. Sabzi, M.J. Afshari, and M. Babaahmadi, “pH-dependent swelling and antibiotic release from citric acid crosslinked poly(vinyl) alcohol (PVA)/nano silver hydrogels”, Colloids Surf. B. 1888, 110757 (2020).
Go to article

Authors and Affiliations

Katarzyna Kazimierska-Drobny
1

  1. Department of Mechatronics, Bydgoszcz Kazimierz Wielki University, Kopernika 1 street, 85-074 Bydgoszcz, Poland

This page uses 'cookies'. Learn more