PLAYGROUND SURFACES: AN EVALUATION OF SURFACES FOLLOWING INSTALLATION TO DETERMINE ACCESSIBILITY FOR CHILDREN WITH DISABILITIES

The playground is a place for play and learning for all children and especially for children with disabilities. When the playground presents physical barriers such as inaccessible surfaces and routes, play, learning, development and the self-actualized benefits of the leisure experience can be stunted or even eliminated for a child with a disability. There are more than 100 different commercial varieties of playground surfaces on the market in 2010. Lack of reliable product performance data on the effectiveness of safe, accessible playground surfaces relative to costs for installation and ongoing maintenance prohibits public playground owners from making informed choices on the selection of surfaces most appropriate for their public setting. The purpose of this study was to evaluate a variety of playground surfaces, their ability to meet accessibility requirements and their costs upon initial installation. The research questions include: how well do various playground surfaces meet the accessibility requirements upon installation? What are the costs for the various playground surfaces and are the costs related to performance? What accessibility issues arise out of initial installation? A total of 25 sites were visited to evaluate the surface conditions for accessibility and gather information on the costs for installation. The playground surfaces were categorized as either poured in place rubber, rubber tiles, engineered wood fiber, shredded rubber or a hybrid surface system. A visual inspection was conducted at nine pre-determined locations within the play area. Locations were awarded a deficiency score at occurrences where the surface location was not in compliance with the minimum accessibility standards of the Americans with Disabilities Act. In addition, the surface locations were measured for firmness and stability with a Rotational Penetrometer. Results from this study indicate that there is no perfect playground surface. Even within 12 months of installation, each type of surface has had some type of issue or series of issues that may affect the product’s performance and contribute to the necessity and frequency of surface maintenance to assure accessibility and safety for use by children on a daily basis.Submitted to the faculty of the University Graduate School in partial fulfillment of the requirements for the degree Master of Sciences in the School of Health, Physical Education, and Recreation Department Recreation, Parks, and Tourism Studies Indiana University December 201

A Longitudinal Study of Playground Surfaces to Evaluate Accessibility FINAL REPORT

The playground is a place for play and learning for all children, including children with disabilities. When the playground presents physical barriers such as inaccessible surfaces and routes, play, learning, development and the self-actualized benefits of the leisure experience can be stunted or even eliminated for a child with a disability. There are more than 100 different commercial varieties of playgrounds surfaces on the market. Lack of reliable product performance data on the effectiveness of safe, accessible playground surfaces relative to cost for installation and ongoing maintenance prohibits public playground owners from making informed choices on the selection of surfaces most appropriate for their public setting. The purpose of this study was to evaluate a variety of playground surfaces, their ability to meet accessibility requirements upon initial installation and maintenance over a five-year period. The research questions include: how well do various playground surfaces meeting the accessibility requirements upon installation? What are the costs for the various playground surfaces? What accessibility issues arise out of initial installation? What maintenance issues arise? Results from this study indicate there is no perfect playground surface. Even within 12 months of installation, each type of surface has had some sort of issue or series of issues that may affect the product’s performance and contribute to the necessity and frequency of surface maintenance to assure accessibility and safety for use by children on a daily basis.U.S. Access Boar

A Longitudinal Study of Playground Surfaces to Evaluate Accessibility: Year One Findings

In 2008, the National Center on Accessibility (NCA) at Indiana University initiated a longitudinal study of playground surfaces with research funding by the U.S. Access Board. The purpose of this longitudinal study is to evaluate a variety of playground surfaces, their ability to meet accessibility requirements, their costs upon initial installation and maintenance over 3-5years. The following information is a summary of year one findings. Data collection for the longitudinal study is scheduled to continue through September 2012, with a comprehensive report of findings to follow.U.S. Access Boar

What voting rules do citizens prefer?

Le système électoral fait de plus en plus objet de débats et de discussions au Canada et ailleurs dans le monde. Bien qu’il existe de nombreuses études sur les avantages et les inconvénients des différents systèmes électoraux, très peu d’entre elles examinent les préférences des citoyens concernant les modes de scrutin et plus particulièrement la façon dont les individus expriment leur choix sur le bulletin de vote. Dans le cadre de ce mémoire, je m’attarde aux questions suivantes : quelle façon de voter les citoyens préfèrent-ils et pourquoi ? Afin de répondre à ces questions, j'ai mené une expérience en laboratoire avec près de 200 participants dans le cadre des élections fédérales canadiennes de 2019. Les participants furent invités à voter dans une série d'élections en utilisant chacune des trois façons de voter suivantes en ordre aléatoire : scrutin à vote unique, vote par approbation et vote par rangement. Après chaque vote, les participants furent informés du résultat électoral dans leur groupe et interrogés sur leur niveau de satisfaction à l'égard de chaque façon de voter. Les résultats démontrent que les citoyens préfèrent avoir la possibilité de classer les partis plutôt que d'utiliser un scrutin à vote unique ou un vote par approbation. Les individus sont également plus susceptibles d’aimer un mode scrutin lorsqu'ils sont satisfaits des résultats de l’élection.Debates over which electoral system would best serve the general public are on the rise in Canada and in other democratic countries. Although there exists a rich literature on the benefits and shortcomings of different electoral systems, very few studies examine citizens’ preferences regarding voting rules and the ways in which individuals can cast their vote. In this paper, I address the following questions: What voting rules do citizens prefer and why? To address these questions, I conducted a within-subject laboratory experiment with nearly 200 participants in the run up to the 2019 Canadian federal election. Participants were asked to vote in a set of elections using each of the three following types of ballots in random order: one-mark ballot, approval voting and ranked voting. After each vote, participants were informed of the election results and asked about their level of satisfaction with each voting system. The results show that citizens prefer having the option to rank order the parties rather than using a one-mark ballot or approval voting. Individuals are also more likely to favour voting rules when they are satisfied with the results of the election

The dispersion of strong field dielectric permittivity in (1-x)PMN-(x)PT ceramics

We propose the method of analysis of the dielectric permittivity measured in very strong electric fields. The method is based on the numeric calculations of derivative from P E hysteresis loop. Such investigations have been performed for PMN-PT ceramics at various temperatures and frequencies. As a result we analyze the low frequency dispersion of the strong field dielectric permittivity

Technology, physical properties and phase transitions in PMN-PT-PS ceramics

Solid solution of (1-y)[(1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3]-yPbSnO3 (PMN-PT-PS) investigated in this paper is based on (1-x)PMN-xPT (PMN-PT) where, with increasing x, the transition from relaxor to ferroelectric properties is observed depending on composition. PMN-PT ceramics with 0.25< x <0.4 has been obtained using sol-gel method and next mixed together with PS ceramics obtained from oxides. Final sintering of ceramic samples was pressureless. We present the results of microstructure and XRD investigations, dielectric permittivity and hysteresis loops measurements vs. temperature.[1] T.R. S h r o u t, Z.P. C h a n g, N. K i m, S. M a r k -g r a f, Dielectric behavior of single crystals near the (1-x)PbMg1/3Nb2/3O3-xPbTiO3 morphotropic phase boundary, Ferroelectr. Lett.Sect. 12, 63 (1990). [2] B. N o h e d a, D.E. C o x, G. S h i r a n e, J. G a o, Z.-G. Y e, Phase diagram of the ferroelectric relaxor (1-x)PbMg1/3Nb2/3O3-xPbTiO3, Phys. Rev. B, 66,0541041-0541049 (2002). [3] A.K. S i n g h, D. P a n d e y, Evidence for MB and MC phases in the morphotropic phase boundary region of (1-x)PbMg1/3Nb2/3O3-xPbTiO3: a Rietveld study, Phys.Rev. B, 67, 641021-6410212 (2003). [4] D. Z e k r i a, A.M. G l a z e r, Automatic determination of the morphotropic phase boundary in lead magnesium niobate titanate Pb(Mg1/3Nb2/3)(1 x)Tix O3 within a single crystal using birefringence imaging, J. Appl. Cryst.37, 143-149 (2004). [5] Z.-G. Y e, Y. B i n g, J. G a o et al., Development of ferroelectric order in relaxor (1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 (0<x<0.15), Phys. Rev. B 67, 104104 (2003). [6] Z. J i w e i, S. B o, Z. L i a n g y i n g, Y. X i, Preparation and dielectric properties by sol-gel derived PMN-PT powder and ceramic, Materials Chemistry and Physics, 64, 1-4 (2000) [7] R. S k u l s k i, P. W a w r z a ł a, D. B o c h e n e k, K. Ć w i k i e l, Dielectric and electromechanical behaviors of PMN-PT ceramic samples, Journal of Intelligent Material Systems And Structures, 18, 1049-1056 (2007). [8] R. S k u l s k i, P. W a w r z a ł a, J. K o r z e k w a, M. S z y m o n i k, The electrical conductivity of PMN-PTceramics, Archives of Metallurgy and Materials, 54, 717-723 (2009) [9] X. Y h a n g, F. F a n g, Study of the structure and dielectric relaxation behavior of Pb(Mg1/3Nb2/3)O3–PbTiO3 ferroelectric ceramics J. Mater. Res. 14, 4581-4586 (1999)

The properties of PBZTS ceramics near osthorhombic-rhombohedral morphotropic phase boundary

We present the results of obtaining and investigations of (Pb1xBax)((Zr1yTiy)1zSnz)O3 (PBZTS) ceramics with x=const=0.2, y=const=0.08, z=0, 0.02, 0.04, 0.06 and 0.08. Ceramic samples have been obtained by conventional ceramic technology from oxides PbO, ZrO2, TiO2, SnO2 and barium carbonate BaCO3. The calcination of powders was performed at Tcalc=850 C/tcalc=3h and next calcinated powders were pressed into discs and were sintered at Ts=1250 C/ts=4h using free sintering (FS) method. For such obtained samples the following investigations have been done: EDS, XRD, microstructure of fractured samples, dielectric measurements, P E hysteresis loops investigations at various temperatures and electromechanical measurements at the room temperature using optical displacement meter. Investigated compositions are close to rhombohedral-orthorhombic morphotropic phase boundary. The results of dielectric and electromechanical properties are typical for ferroelectric materials

A continental rift model for the La Grande greenstone belt

Stratigraphic relationships and the geochemistry of volcanic rocks contrain the nature and timing of the tectonic and magmatic processes in the pre-deformational history of the La Grande greenstone belt in the Superior Province of north-central Quebec. The lowermost supracrustals in this belt are obscured by syntectonic granitoid intrusives. The supracrustal succession in the western part of the belt consists of a lower sequence of immature clastic sediments and mafic volcanoclastics, overlain by pillowed and massive basalts. Further east, along tectonic strike, a lower sequence of mafic volcanoclastics and immature clastic sediments is overlain by a thick sequence of pillowed and massive basalts, and resedimented coarse clastic sediments and banded iron formation. These are overlain by assive basaltic andesites, andesites and intermediate volcanoclastics intercalated with immature clastic sediments. In contrast, in the eastern part of the belt lenses of felsic volcanics and volcanoclastics occur at the base of the succession and pillowed and massive basalts are overlain by komatiites at the top. The La Grande greenstone belt can be explained as the product of continental rifting. The restricted occurence of komatiites, and eastwardly directed paleocurrents in clastic sediments in the central part of the belt are consistent with rifting commencing in the east and propagating westward with time. The increase in depth of emplacement and deposition with time of the lower three units in the central part of the belt reflects deposition in a subsiding basin. These supracrustal rocks are believed to represent the initial rift succession

Electrophysical properties of the PMN–PT–PS solid solution

The (1-y) ((1-x)Pb(Mg1/3Nb2/3)O3–xPbTiO3 )–yPbSnO3 solid solution (PMN–PT–PS) was obtained and investigated in the present paper. For the analysis of the influence of the PbSnO3 component on the electrophysical parameters, the compositions from the rhombohedral phase, tetragonal phase, and a mixture of these phases were selected. The six compositions of the PMN–PT have been obtained using sol–gel methods (for values of x equal to 0.25, 0.28, 0.31, 0.34, 0.37, and 0.40). The ceramic samples of the 0.9(PMN–PT)–0.1(PS) solid solution have been obtained using the conventional ceramic route. X-ray diffraction (XRD), energy dispersive spectrometry (EDS), and microstructure measurements were performed, as well as tests regarding the dielectric, ferroelectric, piezoelectric properties and electric conductivity of the PMN–PT–PS ceramic samples versus temperature. Results of the measurements show that the obtained PMN–PT–PS materials have good electrophysical properties and are well suited for use in micromechatronic and microelectronic applications.1. Angadi, B.; Jali, V.M.; Lagare, M.T.; Bhat, V.V.; Umarji, A.M.; Kumar, R. Radiation resistance of PFN and PMN–PT relaxor ferroelectrics. Radiat. Meas. 2003, 36, 635–638. 2. Shrout, T.R.; Chang, Z.P.; Kim, N.; Markgraf, S. Dielectric behavior of single crystals near the (1-x)PbMg1/3Nb2/3O3–xPbTiO3 morphotropic phase boundary. Ferroelectr. Lett. Sect. 1990, 12, 63–69. 3. Noheda, B.; Cox, D.E.; Shirane, G.; Gao, J.; Ye, Z.-G. Phase diagram of the ferroelectric relaxor (1-x)PbMg1/3Nb2/3O3–xPbTiO3. Phys. Rev. B 2002, 66, 0541041–0541049. 4. Zekria, D.; Glazer, A.M. Automatic determination of the morphotropic phase boundary in lead magnesium niobate titanate Pb(Mg1/3Nb2/3)(1-x)TixO3 within a single crystal using birefringence imaging. J. Appl. Cryst. 2004, 37, 143–149. 5. Gehring, P.M.; Chen, W.; Ye, Z.G.; Shirane, G. The non-rhombohedral low-temperature structure of PMN–10% PT. J. Phys. Condens. Matter. 2004, 16, 7113. 6. Zekria, D.; Shuvaeva, V.A.; Glazer, A.M. Birefringence imaging measurements on the phase diagram of Pb(Mg1/3Nb2/3)O3–PbTiO3. J. Phys. Condens. Matter. 2005, 17, 1593. 7. Shuvaeva, V.A.; Glazer, A.M.; Zekria, D. The macroscopic symmetry of Pb(Mg1/3Nb2/3)1−xTixO3 in the morphotropic phase boundary region (x = 0.25–0.5). J. Phys. Condens. Matter. 2005, 17, 5709. 8. Noheda, B. Structure and high-piezoelectricity in lead oxide solid solutions. Curr. Opin. Solid State Mater. 2002, 6, 27−34. 9. La-Orauttapong, D.; Noheda, B.; Ye, Z.-G.; Gehring, P.M.; Toulouse, J.; Cox, D.E. Phase diagram of the relaxor ferroelectric (1-x)Pb(Zn1/3Nb2/3)O3−xPbTiO3. Phys. Rev. B 2002, 65, 144101. 10. Skulski, R.; Wawrzała, P.; Korzekwa, J.; Szymonik, M. The electrical conductivity of PMN–PT ceramics. Arch. Metall. Mater. 2009, 54, 717–723. 11. Skulski, R.; Wawrzała, P.; Bochenek, D.; Ćwikiel, K.; Dielectric and electromechanical behaviors of PMN–PT ceramic samples. J. Intell. Mater. Syst. Struct. 2007, 18, 1049–1056. 12. Niemiec, P.; Skulski, R.; Bochenek, D.; Wawrzała, P. Technology and properties PMN–PT–PS–PFN:Li material for multilayer capacitor. Arch. Metall. Mater. 2013, 58, 1313–1316. 13. Cross, L.E. Relaxor Ferroelectrics: An Overview. Ferroelectrics 1994, 151, 305–320. 14. Newnham, R.E.; Sundar, V.; Yimnurun, R.; Su, J.; Zhang, Q.M. Electrostriction in dielectric materials. Ceram. Trans. 1998, 88, 15–39. 15. Viehland, D.; Li, J.F. Investigations of electrostrictive Pb(Mg1/3Nb2/3)O3–PbTiO3 ceramics under high-power drive conditions: Importance of compositional fluctuations on residual hysteresis. J. Appl. Phys. 2001, 89, 1826–1835. 16. Guishing, X.; Luo, H.; Wang, P.; Zhenyi, Q.; Zhiwen, Y. Ferroelectric phase transition in relaxor ferroelectric single crystals 0.76PMN–0.24PT. Chin. Sci. Bull. 2000, 45, 1380–1385. 17. Choi, S.W.; Shrout, T.R.; Jang, S.J.; Bhalla, A.S. Dielectric and Pyroelectric Properties in the Pb(Mg1/3Nb2/3)O3–PbTiO3 System. Ferroelectrics 1989, 100, 29–38. 18. Ho, J.C.; Liu, K.S.; Lin, I.N. Study of ferroelectricity in the PMN-PT system near the morphotropic phase boundary. J. Mater. Sci. 1993, 28, 4497–4502. 19. Skulski, R.; Bochenek, D.; Wawrzała, P. Technology, physical properties and phase transitions in PMN-PT-PS ceramics. Arch. Metall. Mater. 2011, 56, 1051–1056. 20. Zhai, J.; Shen, B.; Zhang, L.; Yao, X. Preparation and dielectric properties by sol-gel derived PMN–PT powder and ceramic. Mater. Chem. Phys. 2000, 64, 1–4. 21. Bochenek, D.; Surowiak, Z.; Krok-Kowalski, J.; Poltierova-Vejpravova J. Influence of the sintering conditions on the physical proprieties of the ceramic PFN multiferroics. J. Electroceram. 2010, 25, 122–129. 22. Singh, A.K.; Pandey, D. Evidence for MB and MC phases in the morphotropic phase boundary region of (1-x)PbMg1/3Nb2/3O3–xPbTiO3: A Rietveld study. Phys. Rev. B 2003, 67, 641021–6410212. 23. Koval, V.; Briančin, J. Microstructure and electrical response of 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 relaxor ceramics. Ceram. Silikáty 2003, 47, 8–12. 24. Tailor, H.N.; Bokov, A.A.; Ye, Z.-G. Dielectric characterization of (1-x)PMN–xPT (x = 0.07 and 0.10) ceramics synthesized by an ethylene glycol-based soft chemical route. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 2011, 58, 1920–1927. 25. Perantie, J. Electric-Field-Induced Dielectric and Caloric Effect in Relaxor Ferroelectrics; University of Oulu: Oulu, Finland, 2014. 26. Jo, W.; Dittmer, R.; Acosta, M.; Zang, J.; Groh, C.; Sapper, E.; Wang, K.; Rödel, J. Giant electric-field-induced strains in lead-free ceramics for actuator applications–status and perspective. J. Electroceram. 2012, 29, 71–93. 27. Karapuzha, A.S.; James, N.K.; Khanbareh, H.; van der Zwaag, S.; Groen, W.A. Structure, dielectric and piezoelectric properties of donor doped PZT ceramics across the phase diagram. Ferroelectrics 2016, 504, 160–171. 28. Kumar, P.; Sharma, S.; Singh, S.; Thakur, O.P.; Prakash, C.; Goel, T.C. Structural and Electrostrictive Behaviour in PMN-PT (68:32) Ceramics. Ferroelectrics 2005, 326, 55–60

Dielectric and electrostictive properties of ferroelectric relaxors

On the basis of ferroelectric relaxors electrostrictive ceramics has been obtained. Searching for electrostrictive ceramic transducers with optimal electromechanical parameters include the following: 1) investigation of different types of complex oxides with the perovskite structure (OPS): ferroelectric, antiferroelectric, non-polar; 2) investigation of OPS with different degree of the cation order; 3) measurements of the electrostrictive coefficient (Q), Curie-Weiss constant (C), coefficient of linear thermal expansion (A), polarization (P) and permittivity (e); 4) X-ray structure analysis. The following rules have been stated out during the experimental investigations: 1) values of the electrostrictive coefficients (Qijki) depend not only on the chemical constitution of OPS but, first of all, on the degree of cation order (i.e. the coefficients increase with an increase in the degree of cation order: non-ordered state — simple state — ordered state; 2) products of the hydrostatic electrostrictive coefficient (Qh', and the Curie-Weiss (C) constant of all ferroelectric and antiferroelect.ric OPS are nearly equal; 3) value of the hydrostatic electrostrictive coefficient (Qh) is nearly proportional to the linear thermal expansion coefficient square (A1 2). Taking into account the above mentioned rules the detailed and systematic investigations of OPS with non-ordered cations and high value of the Curie-Weiss constant (C) and permittivity (e) were carried out. In such OPS high value of induced polarization leads to considerable electrostrictive deformation described by the Mijkt tensor (Mijhi ~ Qijkier)- One can mention PbNb2/3Mg!/3O3 and solid solution prepared on the basis of PbNb2/3Mgi/3O3 as an example. Devices fabricated on the basis of electrostrictive ceramics provide a relative displacement of about IO-3 what is few times more than the one provided by devices on the basis of piezoelectric ceramics