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="390"></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: 'managed',cRay: '91c796b57910fd8d',cH: 'DiRcJa0sWvFvxrXm6jJZn7i7D88RcoR1BbQYUh01XUg-1741324250-1.2.1.1-hozwQ5zumnhBCKsZ_1u.L8wIldj._dl6_a7IvQ7ikfTlfKyPc1uchgkOh3.377fw',cUPMDTk: "\/search?q=relaxation%20time%0D%0Aapproximation&__cf_chl_tk=55YzxFpI4zq1GQ8KgqiknIzTLuA5cznlSkTrB.eYVqM-1741324250-1.0.1.1-Se.K2gFNWqTBvKBlO1Nk9CThF0lTxZYl7kpF4RSwiGg",cFPWv: 'g',cITimeS: '1741324250',cTTimeMs: '1000',cMTimeMs: '390000',cTplC: 0,cTplV: 5,cTplB: 'cf',cK: "",fa: "\/search?q=relaxation%20time%0D%0Aapproximation&__cf_chl_f_tk=55YzxFpI4zq1GQ8KgqiknIzTLuA5cznlSkTrB.eYVqM-1741324250-1.0.1.1-Se.K2gFNWqTBvKBlO1Nk9CThF0lTxZYl7kpF4RSwiGg",md: "K2ocYB0BhVUgQn4zXI3oJsPH91tdCchUUi1q8wgmAzg-1741324250-1.2.1.1-eGgMl0GZruIVM5U4eZqqML4G7Su7yB05ejxgJAnYEVBXJZr6Ih_WgL6NH4W4HWTX30zaVeLIE5x3fFFMNu_l3juY8ILIzIK7oJL3zH0v8RTHqxBO9Tq3EEZ24jBI6824XPn7Bw2Ss9oBYVbuGS8XWfaSqALvFV9lCXZ0lLD_DQRV_PCmKVggiiC5pocaNLboHL8JMCmZJ6assFJCdKYr0lJ01KzC4ZTkQ8WE5eBWUvq8pizIO8tP4ttHT2GNPRbsb9uVfHMTnXwrk1Jh_iuxRpRb5MPiOZJ5isgeWh5TuuWdbOk97W6_2P3hdiXO_lXWWWjbcsTs_uc8US2NIGdgig4euexCSqA7BhYIFfSKGnrbmi1Bg.cbETJamj19hC5BXXEX7HDVjYQopfhnVlUt_EceC6QLKXT9S69b7hjjlmrMPYRP03PQpXNUx8l8JoWZQw7zCsvJVNsdWdYcVGGd6OUEeSEFhMR_LASWEd3WxsZ4AEQhDHuOX.s00f4WiXzKA6QQv.Wpb0EOnmlen7M1OV5djnFw6S_UYcr68bNGYFeC2Q1UTiJtorflBj77R2RjHwdzZmIBoHuKNtALd0no3bNTLSbfKxy0_t40RxN4b8Uhb5vOvya0q4o5Kg6ir95UUIKjf2w4_VSG9bIxsakmlOoQ39hqmP0us5uCZf78z1P8nB42NiXP56WCvmT02JVh11Q8CF43lOzWFXSp7vLAto4g2gd_1oedupEAmJTgXpmd301uax1Kq9RGAgKgU24USImwYyPHNZXB.2BtTZUcxY3eRPa_4TaTn54mHL.WifF8ALZAUbtyXQaKUYYnwPxvW0Vr7nDfBTkw9OsqF9nT5sit85YLqND_eXR0HDwAP7rqOlv4XvHqC0t2vFSYgwBjWSTAfNt2XISsZ9Vkva4Q0dfk7aMxAa9mk_dDvo5wYQxEjISIFtQpQBNirlkY64EtKkuw8L6IpOhK1lYFldpJLx_lqbGEOJRnOPtzhgfTXDBCYUJsgVwZ7j7N9YAuKgOHzgwemQRwzVPRL56qcpfxDUJQGjKXojkhJJMVKarEnrqc3hj7LZ3detU5Z2adSFAHC5_YLPAC.fix3Ejw0947EXMc4PBVssbou7MaEUFkPRBJAFfknNKg32BbUXdccC94blwr.ToDIsml4xtznK_oLeWWaIa84aBTIZaTYr4k3wfKwuwrQoak39SLruybA88EYT2ipXFLheuJWZoo8rxjwkKxkhmslDWs5XKKNwPXudLmSqdgPVO_FjV6q6.al_YB4Pq.AZbtddaVtVDwm1gaHE550bQapaygFZpLLdKuotA",mdrd: "OYZWfAvsWfiv05esxp68bckG8CiTITcAGdqD2IZ1bG4-1741324250-1.2.1.1-.ls_yuC5dqzwXFYCI8y7jnVSGBuumyU8PMoyg0TX6PSIWAZo5RpMNBU9cyY3izDb573dKdbijHcAbu3IMFXD.6CnhDAxj9KFOXis5z.oq3FKB6ZKev9kbGnzuHMq_Lj80rXNhhyA1Zvofj4VMoqVzr.27pYhYN75R__JbYqJjQ4JX5dx.KuLiq9wqi6SmVVwPomOoQSYlqekzXRUYtKE4xi4CJTwuVuZUwFJxPi_9ZK4AT16H46ntTMMBJWuLlta2h7ow3VyIJWOM89lzUSm4e9P2wlJXu1WX_ARIgTRJynZBRB6qRVZXQ6ntVsFnFmorin35KiJ0YM58K99hDLv7MAF7dgWfT0glBRE.0pEr2Y3x8t.A.3DF0yNFgrPkYRtWFI9pzxJkywN1YEOVJenVZRsFRVvOd0y9wwRz4p8vk4_UGB4iuIa8hzsW6aLhLHBA5Drk40Pt0XRmz1LD9y8HwjfsT4abO_gJUSsio9X.9yfhDYUKneTyGFmoSbjUgH92jIeus4.npQnj9bpsa8fz.Dpoyy3.7151WVNK5sHBnlMXPg6gdW9bZ1mkkZIlxeq.afJ9SObrOFdPSCrET3IBvb_RQNgtnRA_mxeUvkwkM69DGg72UCwP7FXLYqSoYLa_V7jk6Y4ZQTxOIQ1KPBuSHVa_KQ1RDXKYYFSF1Z5LT2l7mbg3OnEoLFvWzEAeLNL57SLEbE0bGDlczZJMOhdeGeRd8_bYNeuC_oPiiOMLvjDlH_C6Wig0YgyJCbM0aI0Zkf8NHSXUj6yoPJMM79RiQM4RhTlC_rkQ14czisOFLyU0KdD5K8XM03XfiRT16FgDClBUfhyCdQUiPGSyMnO4mLGF88Kv3Q1mQnnCrtoHb6RIvkb6jn6lRG_S7IJQnEvr.677_y0bZtDivP_ud6mG7u.AboAt.HvMTE89vfUBEESD6DA6gtNcOS1uv60F8tYK415uZRlAfYJExlNgeE0NG3WVEGKcDjKk1SndtrWwDo89RzqZnzyTJ.kj0dvCFdYGqmxn4LWtNDK5R7Os.hkVJZMni15LHz9HTWSMuPtU0ElUp3C8V1ULu8KzybYEcNW_N9oZ0JdsLr.MgFsy52laSOkJdH8_V_ANpiWyRVZH8WxZinvoF1l1TrSWYWbv.ugT9d_qXgwAek28LALOMHerXI0qQ3WfFe1MTckrMufLryFbnQ.GhajB1UjktqQe5hST5MFnMoCT6G2BkQ9hNDfv0tlKJ.lYUKByG01yM0qXGpaVWvAzaXe1HWCFCps__fJhMiPpffc.UwBORd6KKitHXACuqwCo_4Y7BT9vl6m36zPvUvCF88suGqQVJQZpDcwGiTD0HOEjXht9iYhK.Kq5HDWqBEpWr4j7Dd1_7qPZblzEPjDP8HAo8RV4CxJNTLPTt5ZH1iFbsDm1e0s.MzaUR.gN_4Zw4hqnzG.GZ6l.RJykY7ce5AFsf_UD7gQSoo9_9kTTm7q9GQ0ME5RWhIlalGTgJ9XRtCTrYur78YFXu2yRZTGlDkY5r3yA_8Y3yT9kt5GSL5BfZThIUqrGz5E85_rB4tlVuePAMIbjS8J3KUEONFojz8xoBfW2dJJLoDGg30bfBvCmjJ4x0vBYGrXQ6R3OqQGxmpW1PjEspzh2SsyiqzQ8juRPg_WCtthKa_w0Ch43Wi4QiWMpnShGPnmSPzxi35P9d_jYbulU3MrIdmNEEydMI6Dez35liEHVOXfb8oLiPC17Q7ozdkBXaCFw5r11t1.cSpnS7o6_PFqe.1nPKM7MxvyzWl._0wSsSvDxBrXYT.hMry4QlvsVFrMteFt2l3uFLpKmBAASLcAurR9mBwU8R7vTf..ovBBD1pfpd5wR35qblIKJpxoIOnJM8_aqnTyv9W2EfdB.vu8ptGgz04E7mq8fmuboeBL2G5tpD1nkw2w6W1oUxZtDJr0MRiVjS.qP8ZQbQjHews1FhNZTpFnuMs2F1eJMuSPknsAY5eCPHSzeoZ5M1hRLvwOPw"};var cpo = document.createElement('script');cpo.src = '/cdn-cgi/challenge-platform/h/g/orchestrate/chl_page/v1?ray=91c796b57910fd8d';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, "\/search?q=relaxation%20time%0D%0Aapproximation&__cf_chl_rt_tk=55YzxFpI4zq1GQ8KgqiknIzTLuA5cznlSkTrB.eYVqM-1741324250-1.0.1.1-Se.K2gFNWqTBvKBlO1Nk9CThF0lTxZYl7kpF4RSwiGg" + window._cf_chl_opt.cOgUHash);cpo.onload = function() {history.replaceState(null, null, ogU);}}document.getElementsByTagName('head')[0].appendChild(cpo);}());</script></body></html>