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: '91355dafdc66ce11',cH: 'BBSc53v8e0Or2w.7BWms7veDZaSRBZXwM7chDi_6rXM-1739790993-1.2.1.1-EIHQE6uxBOmYws7k.Wb4Ko0fcXJT6umWKenIshezoonHE0daMwxusKq93_oY6Mi1',cUPMDTk: "\/abstracts\/search?q=willingness%20to%20pay&__cf_chl_tk=BIs1R0zi4HldWYPtTov21PLODnH1orV8aQaKnXWH1F8-1739790993-1.0.1.1-6S2hd3nXxQwnrYpOQMRvijbFMjri528ks4lpZpLGuoE",cFPWv: 'b',cITimeS: '1739790993',cTTimeMs: '1000',cMTimeMs: '120000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/abstracts\/search?q=willingness%20to%20pay&__cf_chl_f_tk=BIs1R0zi4HldWYPtTov21PLODnH1orV8aQaKnXWH1F8-1739790993-1.0.1.1-6S2hd3nXxQwnrYpOQMRvijbFMjri528ks4lpZpLGuoE",md: "Bc5PGtOfDVg6z_aFzLRFntD7nPJubj_YnZddfc.gpog-1739790993-1.2.1.1-kiUMlrpKXNTiiUaBojKtHwJD.0QWz89.vIr9jR8et0rdBbhJtcdO48Q13USuGwPk4_08XNIhA.HBo0UOBxqUyjbj4twoRKRc8IEdwMEnNQPfL_l3P.4GM0XKzEucZVrG_ffZ0ZqooqnoxEnMjRiLWw7psVOIySLs79eYglukFOdcEbdfgdn72oK41Y0Mfl40HH9Kx6yGp8BSqEGKPQXcsiNN8cerg..UxYc4DffIVJTZtvlhlgy9JLMykaceZbo43UQfX9kuvTsnPsmQvzRfkpTclm7ULYv7QZW.pd2bxjzPt8NF8QW4mX84cJNecHQn67PP.iXhrBkO5RKBOP4RUKfgxfK3ZnAuLBezioe.hdLAn7vdq2BKoPstinb_.dZB3hzC5KNlI7mDUN1lYsEIzQFzz8uPDpj.HzsBn9NAxtwVybaZDKk1agX4YDCX3kvTAG8Bq9SJ2bmzCyy_Uv4NfQI7LFfLFkFMZwS1_bkicz.fxWejcQ81iDURM4W10KI7IolbWgEa3RKRAtyeWRvcyz2CiVru3LaCys7EEgrEQdQjtnT4jpPixw9FwdMe3fUZQuopJY_v8ZgXp3rcwEHEP7pyhDqhQJ0a0oTg8oCiuqttSJLETJRhWhW7s6y94yU3.qKJXvZuPH4h3liW5NhHjZ5inb3wPduvm3L_gloWvNkdfw3KHrIJPI_XhfdkFPGtfrKZ_U7GXo1v18zUHSeLCu6KCzB_4Atw4kk8dj1NOVTJw2U637u2GcDm9UmUtfAFVoc53JaEV5ez6zgBCFE9TQ5zZpAzpPfLw1hH160xTtcKUTlkB_w7bzC1uQnbl5cD5pzOQE3zSaDmVFMCL8p21IYKLGmDFpQHoEAuQ3E_1uslhPEt3RQ_e7e4DG469it5NLxVfElOJ9U2BdLPqqTjDTFu4Ww1CLvZzsGmeDZYVQWxqnt0egaOK.OhqulrNyjbBMc2ZKmdJoM3aFUu6DMpGx0jQEPQdcq7q5Bc.Snij1UwPs1lHNrA4fONAUJD35xvkXynATJqzswzhegQBizjotSmmtOwmmJimQFCXcr5kyAp34IV1RROnNsP4QK_NStnbmcGYKci.YcpMVDtPWZ4juheGHJsASwMuAS6MF5MhYg9KdbYOBzjjqBz.DP83Dxuu_cz0BZo6Z3ba2PoXgn1mJ6MHEnOMapMAuyOrFMEHoAUahqv8yqZrzJmN0agY2Xp20TsjQxjUOscH6FuxWW.ubj5NcgeBTUTZbySiPbJlDD_.jUQ0ZxecIzq_xf2GLGROZPD3b0M4BdEQpySndcpHy52XIYUM6mIsUhhvV_1rUFVB8o2.sOIRT6xA_Ey8Y2yrruzn3LMhZDzUTjtb0vqQvWTtRB8WOUOC1WWkGgYAe.sEiY8DcX..6J_u8svw1ZkFnWVa94ULULJFLjBZOkO.1ONBdGPMCLHkiEebGGqH_AFnx7weteSaKDU5hWAtMi9s49MvMUBqb9HvEePCylkRIkq71VAZhTY2aAXKJISIXMCHkXvsOWNZITvi71xaaDX90ol75S2DvdHCJH_iOsd2JPhtOFODfn5r0w3gKLkiqHTOfZ4wIiCFy31tOOqT1bdYkjBbiXIMNipbmkszQ1rk5O9DGT4NklNsnNaU9CaqDIJuAroiJwu3gXPiA.mAk9qv.GQdWucqJ.Ly2mfOfCZqfiCHE9ZHWR7A5vBUAQh2NOBx0XSK6bUU16tsSw3sdaxVI2TqFgrYA10ydhzMdm6puwVTw1xICmh5IfWFVPEVRU4ownMGhEHAEbwRuYxJprJkr1YtWlircZRS9SN65Z0Q480TQzbDqUHbpmGe_i_eWBrbE0CkgGjOT4KtK5q0b2vuyX0z2RPxLfngVk_sSnxpBNSjywVfoS.xiVcM86k6s46q1c5esqYTTpVs7UMomeLHzzXqpRnmPo3.ro7e7FTbNTLZwHKqZk7SeczSWyuI0GUFzHsZG2BTqrPCd0zUMoo",mdrd: "iaJ4IDtE5kL5CoMNply.nrE21FxDGHQ4EFkv_nl27KM-1739790993-1.2.1.1-ANb80jSkcaLOC84RNt52I96R0km8fiSi6coVIdEF4qbBWPae0tD_nVo4_WtDCS1drkyCHKk.he.co9ZTIbkHNlA62DZzf1iNiwQMqIQkOLEnj0QsUx8vYlQ27WW.FXscnjFPQXq74k.StFRnEMK6VpEqqdkTKCCaHiNWUCdN.NfEFZ.MJtk0yAb_Ih.7bvPwcuL_jW9Rwk254FchczwxhPpvW103vuuB5_BRElT7i19Dr66ABw5p3duaklP1awJwPpet7H6kyuMn8p9vrAQRvKfZIwJVJSAWSeoTtHWX807t9UbkZF1hdhHPTBsZ_rLRfKM6Ndv2FwkkkoRPswWWKWPDwWevzDayCetaft8YXEqgNseJRrDo9tN2cwYBiqR1iFxAjguiwlz1MdzIm42emT1d34OVny3bn7t4VbHPL9_P.EGLv7MrcWgFyB4SrCmXoJdWbKOcH_9c5FU7GZgy_m2uOHDFPUChwtpLWGjUGB9HZKIc0s0a0t9_9hQm3qiV8VSqio_UsJdsU3SJpROz_Zy9fMN_37VjIidaIJS6cBMsqXs8rzu0xYHJyo_xBEWbadvEQrrBGZ0D3pR9SjuDW4jZVW5O32TFPhu2bSHW6j3hlu2bFA_2K0.EJX1wuovkHkc5I0KJy7Oj3FbXlyWFCkgZpwxdwZueCMncUmSwrUXQVlFFFHjYjWL.ylQkqA07wi9Nf98lGajGtof7_MNNjp1J8iVPTPruaTUKTL_PFdAHVqajt_9bX3jD4hlhigVzoW83e1Vx0J8K.qPtyKIVBuR21p.1oebpzcN9LxCkqAxuSB9xKqcXvSE6ei6UpCw5n1LX78IvVeotuv707YfhT4Iqu.WzXdsL73Xe2_nV.ZlHncg9sv7.93zaWQ_k6ItmA5N0dUaLazJTVwGF6SiqrY1a27NCu.dXwfQOscCwdmBOKKHEc4FRMDkjRcciBj4C7ANeyj56ojWplgdzl5y1.m23UmCynizQt48iSWpU.tG2AOA4IORB.xJ2qi.z3Rydwt8VhcOl10lPFlqCUtFEd9TySunNPLVUNtO4Ki.8Dh1jGisNcX9ZMw2peBa9T1fq77VI23kuOY4rI8SzENlSX81jG0Gns.emOQaU6sDxdmlpGJXyPth4w9MClHXfYR7kRxmdeoBCFWqUXUNZJi90x1zpY8HnfT7g3scBvfMExYcq57102cswfbt.rMNa1qnGy_QimqfI9OXS7Ql.lCjHImWD4PRcfOFFCoXmXo0zZ2HI3oRGTwEKI3kwbXLaJmXWOVJ45JHVLVNBWrlhOUyuuxC2Na5_F0NmbKFkx0XXLmfxWktaKEyVEiwwMsWnwIo5oaA80syOkp3DEaqt6A0UBCRM2JEYM5T0ZL.qPVRuIyNdoV06mT8k3wJ9.CbDcfShg0Y2AC7e8V5EOrnzvYUS14mze6MCSxrg7vN_NW.dtmEjJU9v9wQ_5pcOL2blfv0AKlQA_0JIAjiIID3YhPzPoKlCtFMIimRuad2K7Y6Zy.7Ay4O2FoEJnCxOjYS.Drylk4BpFScHUA9xErWIqUm_GGvCq.oaj_zfwgS46vYW61QT6guJ5H7EzcSEom0mSz6DPMAfoVMgH3IHJJnI2Fm7wcmVTa7RJK0vwZanLZLJ9X1dPxSkOxRef4HlcT0eB8TqiHZOx2hl2mFnoiVLaPDmQA0zsqEkyZQZ.tU3_cLKiPRE2TJAwcKPYkO_obcV35FKismNKrglzCl43rCqFrI_O.vtydRf8qSttK1YFN2WazE_xUZODCjlg72NZEIV_dFQXHvYHpQCVxY1wpvUl8TVG37tUQSk977IkTT1.L1O2y69sGoppSU9iRhfWwFbN0sdvMfOqkx7PdeuFYBOOlZcElWqXyUgWUlpGOc6HAYSuvKWrMpfyKz0IYE.Dc5euFLiemZ3L_YwBi0B8rxUHlVQOuYYVYT51V2Oa6.Xk0IMQaZ08JFdvmxeVrKoqSwoAffu"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/b/orchestrate/chl_page/v1?ray=91355dafdc66ce11';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, "\/abstracts\/search?q=willingness%20to%20pay&__cf_chl_rt_tk=BIs1R0zi4HldWYPtTov21PLODnH1orV8aQaKnXWH1F8-1739790993-1.0.1.1-6S2hd3nXxQwnrYpOQMRvijbFMjri528ks4lpZpLGuoE" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>