CINXE.COM

<!DOCTYPE html><html lang="en-US"><head><title>Just a moment...</title><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><meta http-equiv="X-UA-Compatible" content="IE=Edge"><meta name="robots" content="noindex,nofollow"><meta name="viewport" content="width=device-width,initial-scale=1"><style>*{box-sizing:border-box;margin:0;padding:0}html{line-height:1.15;-webkit-text-size-adjust:100%;color:#313131;font-family:system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,Noto Sans,sans-serif,Apple Color Emoji,Segoe UI Emoji,Segoe UI Symbol,Noto Color Emoji}body{display:flex;flex-direction:column;height:100vh;min-height:100vh}.main-content{margin:8rem auto;max-width:60rem;padding-left:1.5rem}@media (width <= 720px){.main-content{margin-top:4rem}}.h2{font-size:1.5rem;font-weight:500;line-height:2.25rem}@media (width <= 720px){.h2{font-size:1.25rem;line-height:1.5rem}}#challenge-error-text{background-image:url(data:image/svg+xml;base64,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);background-repeat:no-repeat;background-size:contain;padding-left:34px}@media (prefers-color-scheme:dark){body{background-color:#222;color:#d9d9d9}}</style><meta http-equiv="refresh" content="120"></head><body class="no-js"><div class="main-wrapper" role="main"><div class="main-content"><noscript><div class="h2"><span id="challenge-error-text">Enable JavaScript and cookies to continue</span></div></noscript></div></div><script>(function(){window._cf_chl_opt={cvId: '3',cZone: "publications.waset.org",cType: 'non-interactive',cRay: '913586639a0c7979',cH: 'lhV2miyNwxe9AwbhJW0CrFvv2QZckA90Hibzcr_b.Xk-1739792661-1.2.1.1-T0920D48f8EFljWHdiH.b44QnSmaSWXSi1esu8SWw7nQ5jDd3yiv8TUH2F.1bwdk',cUPMDTk: "\/11865\/iso690?__cf_chl_tk=o3u66Eac_Km8fFMHmRJ7N8VUTlsi21iv5zgGtFLZfvM-1739792661-1.0.1.1-7Jo.gSYatek3Et.Nrpj2kFldOVkgb.AEY8mmojLZ5dw",cFPWv: 'b',cITimeS: '1739792661',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/11865\/iso690?__cf_chl_f_tk=o3u66Eac_Km8fFMHmRJ7N8VUTlsi21iv5zgGtFLZfvM-1739792661-1.0.1.1-7Jo.gSYatek3Et.Nrpj2kFldOVkgb.AEY8mmojLZ5dw",md: "xD1JZ9f0OHB78j6Wi3lW9KWPa80bmX5hYVr1i6Cbc.E-1739792661-1.2.1.1-rzmB2P13W6cdNIrEAtu08m0ReJoZZfKIJUHz.EpjvuhLqz9EB8H_RscxSdeB36N7CxZpXMkgW2KGQmLvURJsgKoHtjJh8ixdIjUSd8gbiDf_TAjRes8_cJKUf0I4bLpnld8.gCkzlhNOF9seGrJZN3q.Qasj_5yBTtAxOZp3dykvsdqJUhdMnLo5Nu5fi7qeM6Bo_eTC9HOYJ.zefTWQlw7hgmZnpTbVe3MnlSsq9YA6ua127rJ_YgufEErROAG30EohKFNuVYmGFIr9LfmtyxoWznYDa81XhjxKJ3Di.FlJTzHZc2MgESWWI7oDMat.jMiYmCifJuIQwu8mZEzGVjA4VxC.G6YIZ7a_12ghrB6N6mZxCknzT.u1K35U26_fqQJL2O1yrfATf9DCUVhOmRJwp3C7tUWdBva74bQoSGf4w_lTfzewqo52Zvm9nO2oW.9IGeKnpC6NaEsfP6BQIDI0E4Ghi9jXRuK.Fv3XKrlOFUsHATdOmXRvVUG5AYggnyrz5F.0Hkbz02P5Zhs4xf_MyaaGXzJHKvaHfi7RLJCLjOsn9lVm6p.Sk5xhdon5f5T1asFd9xBXytDYN.CYn_B9jfR4OmWLsa.T4.BAYsi2Fn1kE3bLLKOnLHO1_yCL8EmSAMuK8WjZtG5O32bP9YD9x0ebBA_NQSuy.NFyvCcj6W7OCazjKg5nHxWgZRcQjllsGkDwxxFFwRZ7Wq.1WMjhuVuqjYv72fC1mJykRT0Fbt3b8k3wICsMXjgJfyGgpJb36Dk99LACVT20X5is1kXNtrJ5Y5I0zNil.PhTQhLq8CpCEV2fOQp7Ecx6Nlhd85fmvq3OgsfjsDL.lMYlrtXlVMRXuafja81u.UdYceTNeEFl98DmJV_tk77hlG_SeuSXEinj_0GR5_XuhzpRhZ3EjqCx9tHLQtetR7Kr9aE7IQ9vON55qlL7kV4EpgEw4qxffJOUc3ORiD_ZjTdCIBewZFCsPGDQMqu75Ixkren4Yeqyjf9ouy0qCbGI_yWFkAYNVNCtMW.V3HjH9JFkz87TH8dAFhKiCHN0RiQY__ppbBLLkuHC7U_RsQisJXhj8ZLwLo_B94r41OrelOvfzeJPy3MS0x5ZkmqsXOfsjNsiVWkXWf2k_jlInNfavFlcrjupfkTxG.uFSuGNPkL2k0a0g4N_LylAbKE.ZSKYkWvCPeivlZRIcTYqjsX9OmdGW1dQsphdfZio05OwdNIRHrkzqvRXx.SCiA323_UO3lAkArVOFX2kXIMlu4UN3H.4mLylnLtxDyfwnD6iuDHdAF1rIpiC4ni55IqOOKpfZAQ6Qf84kAHSDczXepZRC4bj5WjV7P_RtXVxG3KcGrsNJhFNlXcKZLnbSiZDt5LFW.6OPeRM9lLAywSdC1RU1g4WFY.b43kajZUaKkw.T3LBw3wDWp8nNeEhw39XFf.EQLf8JauCm_JxaSuMmv9pqpnKHwNRPddNSgd.MwbgpGBo5JXuvjNfM8bTjMdR5M0eUFx8evnig22WHcCGK9UJmm7r2VqArwYtbu4exYG2dj9PAc5tZYazJdq8WnxCsKVdDWZf6O2k9rpdWTaxTjP2_buIBuNRbBGG8yZsEkN_ohdaFotWlfw_3Mi4TI5.bPwk.qaNNrYHuPRz6Rl4Ui75cvy26PubCrNHO..vPl2BtXmsm5_m2z1WYbsPaVmZOMYOeQc4hxRMS7IXmHnNG6MdumOWVc3opBIPRKLq7WnyHUpQ8Nh_vsnFQJYRaDMHYS6z.ZCLnybvTcpma.RvPd.s22XggARdnmP0yIVR6tcG0XiS4ii9RZGlt02GND87y_Lsjd6jFP1dIeCwg6eGWA4Nvn1xqcLoS3_KT1WRCx_3_053HIWLLyQKAY65SYTfuR1mI0Y",mdrd: ".CCua0ceixYk0QECGY6QS3lNS4TAETM7qTCNYVRUaBQ-1739792661-1.2.1.1-._7yeKwTR.PIXk4IxjsVY56FBX.agLOevzoY4t9KdqUFn.fy_UIyOnFRcrthN2fHhAJbdZp3CauE00v7eOchFUPCpgf_tI4ldncpQnl6t_hsk58LuC40GiUgumIW1VKSWHpObneSEdtfgO1mBkYR3Glmw6IBnYleK2IAY2_P.A4Ds7zTCbeRMIXHI71wDjZOc.B8dZ.VJoPFWvgB_iv7nCwRqXNLc9Z97xYYS2d9dB5JZ2uuS6WFrPxFhzStFavJgvlhDFrr8pwUxkMRoEexcGl3XpkBMa5zspewE1IVluj1Rx9MAtWygT4qI12xPEBUi5U94lvJQtKFaGowltffgrBZtA_izHrZxkh7Rg8iNF3C.avdADdH_IJImeEpSimiu7l1Caqz22QU3AZsYiVrVg5tMxSxlKJtIzVNYPKwnYZmYixy84aFdLVOGT2hDxlbyHd70EMyHU8IzYRgh5Hc_AwTM5ro_L3LMIf1DQIe39wD70yszUCA9Pb_IF3lZEk5915H7udJNQ.bBdK4AMapDZSNBLUCY0KUrXLiIVN0ZTfL.J3AajuTlJSZvxj7TAmMcYQvHoiLTns1qwOv4sTHLtGda1gg5xXREi.Raqo4tOFasQCspEbT8MN_.mUc4rw47DPGyRo33Gx_UXbtZlLwF0r6f.e5MPpHMI2EnblFLypN0TNf53g73nPLpzrASITeGcTYmGAtlF0p1HPoOnEbzeiQfIypzYhluBHS0vi1bH0ke50zTQhC_.ENjcK_uApYWXynfNu2uaYGiykA2hqd2zttXc8W9F5fEyvCP2WvwjKA35lO4hdIggEvmZOIp7EdRHP3lIdjoczarm9oMl35yWLIN0Df3PJLBXBUuTIy75oza8EkEEKeeoREjDTVCCVDKiH5oOxMNqorLH0VysOXDevqH3DLcglWvMGqIuOiedmuv5XGgPMUFZZtX_wQs3HNPxckdivCH699tVxFd9f1kvXjiKNbAVg8tlxQyl_xIVsjSdv6_3h09SXY3Vay0xQoVKd3jqOsk1E7GTF_8cvrspbw9hQFEWQ64c1VrteA0.lwQE087cf3hXQMDd9tRc5ibCS77bO_garVBOSQa7SuQBSpO3lMKXudzKD5Yv9Y_qrC9E6YdAnzZSLMIsuokQln108Mq9w4qb3Cci6R0MSb7EnapyozPl8tLmiFHa.iqphHuduzOsjB3ylJrrZr_ANylp9xZ2IsEW2Tbxi08YKuasGOlGZNG5UgtJizKm0FwrQbdMVBTATAvg99fhxX_bXZia4sCZC9ANwJgHItVeoFleeFv._0g0cGA4o99uKK880HWavxbVhBWROZgjkjskVTc.bYCPuTNCnEDaMJ2cB6GB9f3ELhWspMaKJAhRjfVenMJQqWq0aZVNXg1RmLQxVRvLoN6imZ1s9kevOtrPlGaZLs2IpVSTSupQMddFcAt2wnZmDe5fKXR7PAyUmNr1rpp2F.BTjCvZTySEnf131mTsv_R3SmAzj18qJGS..9Bda_SlyxeYSrOqG73BckxvFakPJDx7LygF46_5TVcgRrUEV8ncuhHpk4j1Pn8PNSLCi3Rimwncj_6NAd9IKyxIbWdNbwixOlo61j1qiWauVWU0DjSh19l457AHYxyTwPNU8ZeHlNJgzGJXBPnvs9h4Gmx24DFAz0LuW4E0.0unH0TycDSmR5uUUiPqzyPJeIhV9L1UBpQMO3HjFy6ohT70J7I7t7guLe1wdomGrANAdTOiZbKP2OMCxiqacp7GyptIced3pEpv5imqNzZw2zAXW2f_RIraQJeYYfuDO4T9rS6yHqmQRR2w.6wyolP4AGKZzWc0nhBx6TcqW6WH4vREXEpPc69J.1zqUc.5_r.iNr2.JydRvUblbIaIux3YA3T6yZ6XB5OIf6B_2qfYR_50Z.ezWgXaYcgUtWY26RdoCFAQE5Cn6NL.LFrRm12TKjwhRlY8_AFlR5d7obWz1XX0d5"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=913586639a0c7979';window._cf_chl_opt.cOgUHash = location.hash === '' && location.href.indexOf('#') !== -1 ? '#' : location.hash;window._cf_chl_opt.cOgUQuery = location.search === '' && location.href.slice(0, location.href.length - window._cf_chl_opt.cOgUHash.length).indexOf('?') !== -1 ? '?' : location.search;if (window.history && window.history.replaceState) {var ogU = location.pathname + window._cf_chl_opt.cOgUQuery + window._cf_chl_opt.cOgUHash;history.replaceState(null, null, "\/11865\/iso690?__cf_chl_rt_tk=o3u66Eac_Km8fFMHmRJ7N8VUTlsi21iv5zgGtFLZfvM-1739792661-1.0.1.1-7Jo.gSYatek3Et.Nrpj2kFldOVkgb.AEY8mmojLZ5dw" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>